Menu Search
Jump to the content X X
Smashing Conf New York

We use ad-blockers as well, you know. We gotta keep those servers running though. Did you know that we publish useful books and run friendly conferences — crafted for pros like yourself? E.g. upcoming SmashingConf New York, dedicated to smart front-end techniques and design patterns.

What Is The Worst Design or Programming Mistake You’ve Ever Made?


Mistakes are made every day in the design and development world. It’s nothing to be ashamed of; it happens. In fact, mistakes are one of the most powerful learning tools at our disposal. Our mistakes impart important lessons that we carry with us as we continue to hone our skill set. Own your mistakes. Never shy away from them; they are the milestones in our development.

So often we view mistakes negatively and let them get us down. We believe they indicate failure and that our otherwise perfect record will be forever marred. No one is perfect; we all make mistakes. They indicate failure only if we fail to learn from them.

How often have you stayed late, trying to get something done and did some embarrassing mistake instead? We can learn from our mistakes and mistakes of our colleagues. Image credit2

The online design and development community is a wonderful resource in this respect. Not only are members open about their mistakes, they share their experiences as learning opportunities for others — this is helpful for those of us who have not yet suffered through the same bumps in the road.

With this in mind, we turned again to our Twitter followers3 and Facebook fans4 to find out about the worst design or programming mistakes they have ever made. Now we share them with you, our readers, so that we can all learn from them and avoid making the same mistakes.

Bait And Switch Link

The first common mistake we should learn from — and which several of our followers have had to face — is the old bait and switch. It occurs across the spectrum, for the newb and the accomplished professional, because it’s an easy mistake to make as the working hours add up. What is the bait and switch? It happens when you’re working on one version of a website or project and, at some point during the tinkering, you accidentally switch it for the active website or project before it’s ready.

When we’re in a constant back-and-forth workflow, getting mixed up is easy, at which point the bait and switch can happen. And it causes all kinds of chaos and headaches. Awareness and caution are needed to prevent this error from being part of your personal experience. Before you finalize changes or processes, be sure you’re working with the right file and uploading to the correct location. This isn’t a sure-fire prevention plan, but it will certainly improve your chances.

What Our Followers Said Link

  • “I accidentally put a half-finished (with massive broken bits) update of a website over top of the current live one without a back-up.”
  • “I sent $10,000 worth of product to a customer while testing an ordering portal.”
  • “I deleted an actual repository instead of a working copy. #svn”
  • “Worst programming mistake: editing off a live server and then uploading an old version of the website. All files lost!”
  • “Sat on the development FTP for half an hour, being mad that the live website wouldn’t update!”
  • “Moved the entire directory of websites on a live server into a different folder, then lost it or deleted the in-house CMS”
  • “Programming mistake: writing data to the wrong database.”
  • “Uploading to the dev website FTP and wondering why the live website wasn’t changing, which sent me around the bend in the process!”

Falling Behind On Back-Ups Link

Given that back-up-related mistakes usually come to light once you realize you’ve just pulled a bait and switch, we’ll tackle these next. Problems with back-up files are common in the design and development community, and they are openly lamented. For some reason, though, many of us still find ourselves panicked when we realize we have no current back-ups of the project we’re working on. And it usually hits us just after we lose the active version of the project and need it replaced.

We can take steps to save elements of our work and prevent episodes like this from becoming remorseful blog posts. You can be either low-tech or high-tech when you address this potential problem, but you need to do something. It could be as simple as making a list of details to check daily, and backing up data could be the final step. Alternatively, you could pay for an automated back-up service that guarantees completion of the task. There are several options, each with pros and cons, so find one that works for you and implement it post-haste.

What Our Followers Said Link

  • “I moved a dynamic, CMS-contained website across to a new server. Forgot to back up, then deleted templates in the process. D’oh!”
  • “Mistake: not backing up a compiled Flash slideshow, replacing it, then realizing the new version was completely broken.”

Measure Once, Cut Twice Link

The next mistake we’ll cover happens fairly often. For any number of reasons, we end up measuring once and cutting twice, so to speak. The measurements we work with vary greatly from project to project and from Web to print, so we need to be alert to what we are sizing and aiming for. Sometimes it isn’t so much the measurements as it is the content that requires a re-cut.

Often calculations, measurements and the concept phase need more time than expected. Turning off the computer and getting back to the sketch board or a notebook is often very useful to avoid mistakes. Image credit8

Chalk it up to being overzealous or getting sloppy in our work as we push toward deadlines. If these are the reasons for our re-cuts, prevention is easy: just avoid those things… which is easier said than done. Still, if we mind our p’s and q’s and double-check everything before submitting it, our chances of embarrassment decrease. Follow the carpenter’s old rule of thumb, “Measure twice, cut once” — it benefits us designers and developers, too.

What Our Followers Said Link

  • “Mistake: having 20,000 cards printed that didn’t fit into a lanyard card holder”
  • “Got my colleague’s phone number wrong on her business card… We ordered 2,000.”
  • “This isn’t really a programming mistake, but the most embarrassing mistake I’ve made in Web design was buying a domain name that had the client’s name in it — but part of the name was wrong. Good thing domains are cheap!”
  • “I managed to drop an ‘m’ off ‘millimeters’ in InDesign. Ended up with an 88-meter-wide business card. Schoolboy!”
  • “I think most of us have experienced the horror of hitting ‘Send’ on an e-blast, only to quickly realize it’s wrong.”
  • “Mistake: when I post something and then two weeks later or more, I find out something’s wrong with it.”
  • “A couple of years back, I made a beginner’s design mistake with print: envelopes and paper didn’t match.”
  • “Sent PDF to the printing house for 1000 leaflets. Received them and realized that the phone number was wrong. Then, sent corrected PDF, received leaflets and realized that the wrong PDF was sent. We had 1000 useless leaflets with the right number but with the ‘iStockphoto’ watermark on every (lo-res) picture. Third time it was OK.”
  • “I dropped an ‘L’ from the word ‘public’ in a school prospectus (and website). Honest mistake!”

Miscommunicate Expectations Link

Another problem encountered by designers and developers that you can learn from before encountering it is a breakdown of communication with a client or boss. Many of us let things become unclear or slip by, which makes us unsure whether everyone involved in a project is on the same page. Usually this is caused by a lack of confidence in ourselves or fear that asking for clarification would reflect poorly on us. Whatever the reason, we decide not to revisit the issue and instead proceed with a shaky understanding of what we’re supposed to do.

Every time we communicate with our boss or client, we open ourselves up to the possibility that one or two ideas might get lost in translation. We should be as clear and concise as possible in our discussions so that work stays on track… at least on our end — we can’t control others. If we’re dealing with someone who is unfamiliar with the design and development field, understanding what they’re asking for can be tricky. Take notes, and go over them with clients at the end of meetings so that everyone understands where things stand. Good notes prevent communication blunders.

What Our Followers Said Link

  • “I underestimated the amount of content that two different clients wanted. Not a clear picture from the start.”
  • “For my part, I must say, not reading a ticket well enough and spending two days coding something that wasn’t asked for. Over-enthusiastic FTW!”
  • Emily B.: “My mistake was telling my current employer than I have some experience in Web design (meaning HTML and some CSS); now it’s part of my job to learn how to code ASP and maintain and redesign our entire e-commerce website. Ugh. I’m a print designer!”
  • “I’m in the same situation as Emily. Job description and interview included ‘some Web,’ and now I’m trying to learn PHP and run a full searchable retailer list for my company! Thank God for online tutorials!”

Careless Coding Link

When it comes to coding, we can easily drop the ball. Coding is an in-depth process, in which many different layers are stacked on top of each other, and one can get lost in it. This is one reason why developers comment in their code: so that they leave trails of breadcrumbs throughout their projects. This is a good habit to form, but sometimes it leads to an embarrassing faux pas or frustrating hours of rebuilding, as revealed by our followers.

With just one misfired keystroke, a project can go from a coder’s dream to a virtual nightmare, with no perceptible way out. As if that’s not enough, our coding comments can bite us in the back end, especially if we’ve thrown some nonsensical, fun or unprofessional bits into the code and forgot to remove them. We need to be mindful as we code and avoid distractions as much as possible to avoid burying mistakes so deep that they reveal themselves only after hours of careful combing. Also, take one last look through your comments to be sure you’re not leaving something that you’d rather others not see.

What Our Followers Said Link

  • “I left some profanity in a client’s HTML once while testing text-indent (off-screen position). Very, very embarrassing.”
  • “Accidentally leaving things like ‘Mooooo’ and ‘Baaaaa’ in code that has gone live!”
  • “I used to write haiku in my code to mark my place, and I think I forgot a few out there somewhere… not anymore!”
  • “I once did (as root) `rm -rf tmp /` instead of `rm -rf tmp/` on a Friday afternoon. Painful weekend.”
  • “A typical one: Using = instead of == in an if statement. Always takes quite some time to figure out.”
  • “Typed rm -rf .* on the server. @wsttn wasn’t happy when I deleted everything.”
  • “Using a body * { text-align: center; } on a log-in form, but accidentally placing it in the default style sheet instead of the specific log-in style sheet. Our largest customer didn’t like it when it went live.”
  • “I removed the ID from the ‘Submit payment’ button, and the website failed to take bookings for six hours. Lost £20,000.”
  • “Forgot the where clause when testing SQL to a user table. No fun, I tell ya!”

Forgetting The Filler Link

Sometimes we forget to redact our coding comments and leave in an embarrassing tidbit or two. There are also times when we accidentally leave in filler content. That’s not necessarily a problem unless the client does not recognize it as filler, because then they might not remove it either. Remember that clients, especially the less technically savvy ones, are probably extremely paranoid about deleting anything, so any filler you forget to pull will inevitably be published to the masses.

Again, it comes down to vigilance. We can’t stress enough — on top of all the other stresses in the design and development field — the importance of double- and triple-checking all of these elements before labeling anything as complete. Certainly do this before turning anything over to the client. Making a generic checklist for every project you take on will help you avoid these mistakes. Remind yourself somehow to watch for elements that tend to slip through the cracks.

What Our Followers Said Link

  • “Forgetting to remove nonsense words (used for testing) in an assignment and losing marks. Otherwise, perfect code.”
  • “Two words: dummy data. Strictly ‘Lorem Ipsum’ ever since.”
  • “One time I left an unkind phrase about a client in the comments, and they found it later on.”

Wrong Tool For The Job Link

The last mistake we’ll discuss in depth usually occurs early on in our experience in the design and development field: using the wrong tool for the job. It does happen, and more often than we’d like. When you’re unfamiliar with a field, you’ll sometimes use the wrong platform yet believe you’re on solid ground. At some point, you find out that the program, a supposed godsend, is not compatible with your client’s program or the program of others involved in the project.

Wrong tools doesn’t necessarily mean your coding or designing applications, it also can mean a wrong environment or computer setup. On the photo above, the setup looks solid and well-organized. Image credit10.

Communication can assist in this area, though not as much as research. Find out from your client exactly where the project is going, and contact them yourself to ensure that files will be delivered in the proper format. You can leave this to the client, but you are responsible for ensuring compatibility, so it’s best not to leave it to someone else. Also, as you transition to new areas, research the tools of the trade to avoid making this mistake.

What Our Followers Said Link

  • “I tried to deliver my very first program for Notts County FC to the printers in MS Publisher. I cringe even now.”
  • “The first Photoshop website I ever did was a sliced PSD with all of the content in images… That was back in 1999/2000.”
  • “Using Drupal to do ‘quick ’n’ dirty’ websites. They were dirty, but they sure weren’t quick.”
  • “Designing a database app: rather than de-normalizing data, adding/removing table columns on the fly. Long time ago!”
  • “Hard-coding a navigation across 10 pages instead of using an include. Was new to Web dev at the time.”
  • “Depending on an external source for data and, because that crashed, our website crashed. Almost cost me my job.”

More Mistakes To Learn From Link

Below are several more community-contributed pearls of wisdom that we can learn from. We’d like to thank our dedicated followers who revealed their biggest mistakes so that we could benefit from their toil and trouble.

  • “Mistake: severely undercharging for a massive job. My very first freelancing job. Was not worth the time and effort!”
  • “There was a time in the ’90s when I thought Papyrus was beautiful. *Hangs head in shame*”
  • “I once created an iteration of a logo using Comic Sans, and it was chosen! I’m not proud, but I was young and naive at the time.”
  • “Used Comic Sans for something serious.”
  • “How about 90,000 alert emails sent to four people over one weekend (myself, a colleague and website owners) = 360,000 emails.”
  • “Deleted the shopping cart table from a live website instead of deleting one of the records in the table.”
  • “The worst programming mistake I made was to develop an admin area with cookies only (without other security systems).”

Further Reading Link

Here are a few relevant articles you might want to check out. Definitely worth reading if and when you get the chance.

What about you? Link

What is the worst design or programming mistake you’ve ever made? And if you’d like to participate in other discussions and contribute to articles like this one, follow us on Twitter15 and like us on Facebook16. We are looking forward to your insights!


Footnotes Link

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11
  12. 12
  13. 13
  14. 14
  15. 15
  16. 16
SmashingConf New York

Hold on, Tiger! Thank you for reading the article. Did you know that we also publish printed books and run friendly conferences – crafted for pros like you? Like SmashingConf New York, on June 14–15, with smart design patterns and front-end techniques.

↑ Back to top Tweet itShare on Facebook

Rob Bowen is a staff writer for Web Hosting Geeks and Top Web Hosting, a longtime freelance designer, and burgeoning videographer and filmmaker whose creative voice and works can be heard and found around the web.

  1. 1

    I processed a charge to my credit card while testing the connection between the cart and the payment processor…completely forgot to change it to test mode before doing so. $217 later I found out it worked.

  2. 3

    Well I can recall when prepping a banner to display on the corporate homepage, I instead uploaded a screeshot of my desktop, at a res of 1600 x 1200. Talk about breaking the site.

    Lesson learned here: Test test test!!

  3. 4

    Years ago, I wrote a custom web app for sending out e-mail blasts and messed something up in the code so that depending on your position in the list of people being e-mailed, you’d receive the e-mail that many times. So if I were number 1,200 on that list, I’d receive 1,200 copies of the e-mail. The worst part was that it really was a very simple programming error. With disastrously huge consequences.

    Oh, and the worst part was that the bug came from a last minute fix and to test the fix, only one e-mail address was used. So this code went live and was used to send out a blast to 4,800 people the next day.

  4. 5

    I received dirty scans of artist’s photo’s to be used on her album artwork. I had little time. I cleaned them up. I removed her signature mole. I did not receive appreciation from artist.

  5. 6

    Chris Schneider

    September 10, 2010 4:54 am

    Mine would have to be like many other people’s ‘big’ mistakes, I edited a site in dev, set everything live, without realizing that I didn’t download the newest source code…lots of work down the drain.

  6. 7

    Putting a site live but leaving debug mode on.
    Wouldn’t be tragic, but it had some wrong links on it.. Instead of nice 404 pages the customers got “weird pages full of strange words”. – Classic ;-)

  7. 8

    Dougal Campbell

    September 10, 2010 5:06 am

    This wasn’t too bad (and I’m sure I’ve done worse things that I just don’t remember right now), but I was once a web developer at a trucking company. As a joke, on our dev server, I made so that if you clicked the image of a truck on our home page, it appeared that the headlights turned on. It was just an internal thing that my fellow devs and I knew about.

    Until I accidentally uploaded that change to the live server along with some other changes. I didn’t know it had happened until one day we were in the middle of a project status meeting, and one of the upper managers happened to point it out. Fortunately, he thought it was neat, and I didn’t get in trouble over it. But when he said, “look at this”, and clicked on that truck, my heart stopped for a second.

  8. 9


    I did the same thing. I remember it being that I wasn’t closing the mail object before the loop so it was constantly adding recipients on each loop. I was testing to my email, so it was cancelling out the multi recipients on each mail as is was the same one a hundred times.

    Let’s just say this went out to a big list and I brought down multiple mail servers with many threats of law suits.

    I still have nightmares about that one.

  9. 10

    My first week in my new job and I was charged with re-designing all our companies business cards. We ordered 1500 cards for each of our 75 employees. I only had one mistake out of all those different cards, the only problem is that one mistake was on the CEOs card!!!! He didn’t think it was funny!

  10. 11

    Delete the wrong http://ftp…. The first day of one website, he is off line, bad for the buzz…

  11. 12

    My worst one was when I was cleaning out my development database and deleted a table. Turns out I accidentally deleted a live table, which was user-generated content for about 20 employee websites.

    Luckily Google had cached copies of those websites, and 5 hours later I was able to restore everything manually.

    The end result of this? New backup procedures.

  12. 13

    Better or worse

    September 10, 2010 5:23 am

    The worst mistake? Dropping databases while migrating from an old server to a new one, many GB’s of PgSQL data had to be restored…it’s just not my thing.

    In the early days of webdev my collegue (no really, it wasn’t me) built a webapp with full SQL queries in requestparameters, visible to every visitor…no need to talk any further, right?

    Create infinite loops while importing customerdata with email-blasts, thousands of mails sent in a few minutes, phone kept ringing, had to shutdown a mailserver and clear all queues.

    Sure thing, I can go on for hours, still make a living by programming ;)

  13. 14

    I was designing a logo for a start-up and I had like 3 projects. I wanted to look creative and pro so I added to my nice logo selection other projetcs that I didn’t like much.
    Of course they picked the worst one and every time I see that logo I think “why wasn’t I more confident at the time”.

    Now I only present projects I’m convinced with, even if that means comming with only 2 propositions

    • 15

      It’s funny that! Makes me wonder why clients don’t understand the good and bad design. I have that problem with my more “mature” clients.

    • 16

      this happens every time, and it’s happened to me! a logo i did years before, and the worst part is this is now one of my retainer clients so i have to look at, and work with, it all the time.

  14. 17

    Designed a brochure for a funeral. Left the deceased persons name out…

  15. 19

    All of the #smquestions should be processed like this. Good job ;)

    • 20

      Vitaly Friedman

      September 10, 2010 11:50 am

      Actually, that’s what I had in mind when asking questions on Twitter, too! Glad you liked it!

  16. 21

    I once used filler text for an Ice Cream parlour website. I didn’t know the Guardian were running a top 50 ice cream places article in their colour supplement. They still get asked for chicken and mushroom flavour!

    As someone said earlier, always Lorum!

  17. 22

    Let a client see one of the concepts in Photoshop for a gallery website he had requested, not realising that when I asked him for feedback on the design and usability, he would be disappointed that what he saw for the first time live was nothing like what he had seen and apparently liked in the beginning….Therefore making the 30+ hours I had spent hard coding and writing js that I never had worked with before ridiculously a huge waste of my time….but invaluable learning all the same.

  18. 23

    Once did (as root) a “chmod -R 777 / myfolder” instead of “chmod -R 777 /myfolder” on a live server. Spent 2 days and 3 nights to reinstall and restore everything.

    • 24

      HAHA ( i shouldnt laugh ) , but easy ebough to do.


    • 25

      Lol! once I (as root) did a chown -R me myfolder / instead of chown -R me myfolder/ on a VPS, the administrator was to angry that we couldn’t recover the VPS. Jaaaaaaaaaaa!

  19. 26

    I once built a template for a client that had two distinct page layouts (home and inner-pages).

    The client asked if I wouldn’t mind copying in his text for him, for “about 10 pages”.
    As it was a charity, and he was really nice, I agreed.

    Then came the content, sent as .bmp screenshots for 17 pages (split across around 40 image files).

    I hate manually typing content…

  20. 28

    I was trying to figure why methodXYZ() was not working properly, so I spent 3 hours making different versions of the code, none of which would work. After these 3 hours I figured I never called the method: //methodXYZ();

    Solution: Broke classes into subclasses.

  21. 30

    Using a shift track program for a staff of up to 8,000 I clicked a nameless little check box at the bottom of the analysis page (stupid place for a check box) which crashed the system and wiped 2 years worth of data. Took the company just over a month to recover all the data from a back up.

  22. 32

    I want to buy stock photos for 220 PLN but i didn’t pay attention to currency and pay with my credit card 220$ which cost me like four times more

  23. 33

    I did a site for a healthcare clinic and it turned out awful because of time constraints and I was just getting into hardcore design.

    Ironically they loved it, but I hate everything about it. So much so that I offered to redesign it for FREE.

    I actually demoed the site for a panel and found out the hard way why you should make a site IE6 compliant.


  24. 34

    Simple but EPIC.

    Overwriting a style sheet with the WRONG style sheet on a live site and not having a back up. Errrrr.

  25. 35

    Left some “test profanity” in a programming project in college once. Recently lost a lot of sleep working on a DVD because I failed to catch all the errors in the raw video and menus before transcoding, which takes a LOT of time. When I was redesigning the web page for the same client, (their old page was made from nested tables) I found a couple pornographic images the former dev had put in one of the image folders. They weren’t used in the site anywhere, but it was funny to find.

    On a side note, the mistake of using “=” instead of “==” in an if statement can be avoided a lot of the time if, in the case of comparing a variable with a constant, you put the constant on the left of the “==.” “x = 3” compiles, but “3 = x” does not, and it will alert you to the mistake. Learned that on my first job after college.

  26. 36

    Thanks for all the follow-ups! It’s always great to see the post keep going in the comments like this!

  27. 37

    Lesson #21525:

    When building up that prototype web app, the demo data will eventually seen by anyone connected with the project.

    I was building a medical web app, and filled the database with Bart-esque silly names for patients mainly for our own laughs and under non-demo logons that the devs used for testing, many of them downright lewd: “Seymour Butts”, “Anita Drenk”, “Phil McCracken”, “Dick Paines”, etc… Separate logins for the demos didn’t have these names.

    Lo and behold what should show up when demoing new reporting functionality that went across profiles! To the stakeholders no less. High level admins and department heads. Luckily enough, none of the really bad ones showed up in that run and the docs had a good sense of humor. They actually laughed up the names and suggested others, no doubt getting some of their own frustrations out.

    However, we went back and culled out all the names… and I changed my pants.

  28. 38

    Ran link checking software on a site with auto error email notifications. Found a dead link, found a dead link on the 404 and went into infinite loop.

    Caused 11,000 emails to be generated to my colleague. Boss was away for a month, effectively disabled entire company email by crippling it. Had no passwords, so cringed to use my womanly charms to get password reset for a central webmail, use software to download headers.

    Took 3 days in the end for email to be returned to normal.

  29. 39

    I wrote “fart” as an error message in a conditional if the result set returned false (thinking I would go back and change it after I tested it) A few days later the error shows up on the website and my client asks me why the website saids “fart” on the homepage lol.

    • 40


      • 41


        This rings bells.

        I once worked on an internal system for sales people and was having some serious problems debugging a strange error they were having when inputting wrong data just through utter stupidity.

        After many hours of frustration and comment profanities I fixed it and set it live.

        Got a panicked call a day later asking why the sales manager got the following message:

        “Please enter some proper data you f***ing hob nob or this system will start to delete all your sales commission points in 5 seconds… This fix had better work or I may cry…”

        Needless to say I got severely reprimanded… just wish I could have seen the look on his face!

    • 44

      LoL! Made me giggle at work, this is too good.

    • 45

      Valerij Primachenko

      September 10, 2010 1:16 pm

      i used “Shit happend” as error message on a ticker-reservation platform, when the tickets was sold so somebody else, while the user was checking out. Made my client laugh for 2 minutes.
      Also used the RageGuy as icon for fatal error messages.

  30. 46

    Forgot to remove highly inflammatory phrase* in validation summary on a registration form for a nationwide transport company. Have i learnt from it – probably not!

    *which was there in the first place to remind me to remove it

    edit: this seems to be a popular mistake, glad I’m not the only one

  31. 47

    @hambone. I’m sure everyone has heard the apocryphal airline mailer howler.

    The airline was going to send out a mailer to all its more affluent First and business customers.

    A dev was testing the mailer script and called the name and address database rich_Bas**d. As is the way of things, this got forgotten and then there was a goof-up somewhere and instead of calling the contents of the database for the Dear…. in the mail merge, his script called the database name, so 30,000 letters or so went out addressed Dear rich_Bas**rd. Apparently it had the highest ever recorded return rate.

    As was said earlier, test test test!

  32. 50

    While moving from doing freelance to a full-time web dev job with a firm, I took on a project for a client that I didn’t have time for. I ended up only being half finished by the time the deadline rolled around.

    Never again! :P

  33. 51

    Ah yes… the heart stopping feeling.

    mmm my name is on this post! Anyway…

    I uploaded some changes and had made ONE little mistake… so it bought the entire website down. Then they were kicking my ass for it and saying that I was no longer allowed to upload anything that day cause they had enough disturbances for the day… I knew exactly what was wrong so I did it anyway as I was fully confident it would work.

    I backed up, uploaded, reloaded the page… boom blue screen….. ok ok I’ll just upload the backup. IT STILL DOESN’T WORK! (This is a site with 30k visits a day)

    My went all woozy like I was going to faint, my head got hot and I got the feeling where a camera is on you and it zooms out… and your world expands and you get smaller… I’ve never felt so close to fainting in my entire life.

    Thankfully the blue screen was cached on my local machine… when it worked in another browser I just closed everything I was doing and ignored it.

  34. 52

    Did some testing on a live website in order to fix an issue, as a result, I created a lot of entries in the ecommerce `prices` table which I wanted to tidy up after fixing the issue.

    I ended up executing something like this: delete from `prices` where `id` > ‘248’

    Lessons learned: Mysql does not type cast. Always do a SELECT query before deleting

  35. 53

    I updated a flash gallery on a major betting website, everything seemed ok… Only to find out later that it would completely disintegrate on lower resolutions. They cut my pay b half for that job, and rightly so!

  36. 54

    This inspired me to share mine in a post.

    It was changing the WordPress site address on what I thought was my dev site but was actually the live client site. It made their site redirect to my dev site. I didn’t have access to the database to change it right away and that was terrifying.

    I since learned you can actually change it in wp-config.php

  37. 55

    I am so glad I am not the only person that does idiotic things!! These comments are making me laugh HARD!

    I once overwrote an old website with a ‘new’ barely started one. My life flashed past my eyes as I realised I had taken no back up. I have also made a huge mistake of uploading someone elses index file and an estate agent had a jewellery site at their homepage for god knows how long. whooooooooooooooooooooooooops! I have massively learnt my lesson now though!!!!! BACK UP BACK UP BACK UP!!!!

  38. 56

    Erased the dev database a few weeks after the site went live… but I had forgotten to change the configuration file and the live site was using the dev database. Luckily the CMS has been barely used by the client !

  39. 57

    Warren Benedetto

    September 10, 2010 8:07 am

    I’m pretty sure I made one of the stupidest programming mistakes in history. It’s so stupid, I actually brag about it.

    I built a CMS for a very busy news site. Everything worked all through testing and QA with no problems. But the second day after the site launched, the CEO called at 5AM and said all the news had disappeared. Sure enough, the entire news table in the database was empty. I fixed what I thought caused the problem, then went back to bed.

    The next morning, again at 5AM, I got the same call. All the news was gone. Table was empty. My brain was fried since it was so early, so I hacked in a quick mysqldump of the news table so there would be a backup in case it happened again.

    Later that day, I realized that I needed to change the mysql tables to InnoDB and use transactions, so failed inserts in the publishing process would roll back the deletes that happened just before. Easy fix. Problem solved.

    Flash forward five years later.

    Editors on the site are complaining that publishing stories is realllly slow. I keep telling them it must be their internet connection, because that code hasn’t changed in five years.

    And it hadn’t.

    After months of complaints, I finally went back into the code to see what was going on. Yep, you guessed it:

    That mysqldump was still in the code.

    When I first hacked it in there, it didn’t matter because there were only a few hundred rows in the table. It executed instantly. But after a few years, the table had over 100,000 rows. It was dumping them to disk every time a new news story was published.

    Wait, it gets worse.

    Did I mention that the mysqldump was INSIDE A LOOP?

    It was.

    On average, there were 300 to 400 news stories on a page. That means that every time a story was published, it did 300 TO 400 mysqldumps of 100,000 row table.

    *takes a bow*

  40. 60

    Nikolas Sildeyna

    September 10, 2010 8:51 am

    Accidentaly flatten a 25 hours .psd work. and saving it. then…… quit the program & sleep.
    Imagine when i woke up opening that file for approval and development. &*%^*$^&^$%

    • 61

      I feel for you … I also managed to do that once.

      Another biggie was deleting layers inside a PS smart object that was used more than once, then saving. “Where’d dat go!”


↑ Back to top