This is something I'll never forget.

I'm a senior UI engineer. I was working at a digital agency at the time and got tasked with refactoring and improving an existing interface from a well known delivery company.

I open the code and what do I find? Indentation. But not in the normal sense. The indentation only went forward, randomly returning a bunch of tabs back in the middle of the file a few times, but never returning to its initial level after closing a tag or function, both on HTML and JS.

Let that sink in for a minute and try to imagine what it does to your editor with word wrapping (1 letter columns), and without (absurd horizontal scrolling).

Using Sublime at the time, ctrl+shift+P, reindent. Everything magically falls beautifully into place. Refactor the application, clean up the code, document it, package it and send it back (zip files as they didn't want to provide version control access, yay).

The next day, we get a very angry call from the client saying that their team is completely lost. I prove to the project manager that my code is up to scratch, running fine, no errors, tested, good performance. He returns to the client and proves that it's all correct (good PM with decent tech knowledge).

The client responds with "Yeah, the code is running, but our team uses tabs for version control and now we lost all versioning!".

Bear in mind this was in 2012, git was around for 7 years then, and SVN and Mercury much longer.

I then finally understood the randomness of the tabs. The code would go a bunch of tabs back when it went back to a previous version, everything above were additions or modifications that joined seamlessly with the previous version before, with no way to know when and so on.

I immediately told the PM that was absurd, he agreed, and told the client we wouldn't be reindenting everything back for them according to the original file.

All in all, it wasn't a bad experience due to a competent PM, but it left a bad taste in my mouth to know companies have teams that are that incompetent, and that no one thought to stop and say "hey, this may cause issues down the line".