when your co-worker instead of commenting a piece of old code wraps it in:

if (false) {
...
}

Took me 2 hours to figure out why my changes weren't working.

Instead of deleting*

Had a similar thing at work the other day where we merged two branches together and some old debugging code got merged in.

Took us hours to work out why admin was always able to bypass security. An old developer had clearly got fed up of the security and written something to bypass it!

I take personal offense to this 😂😂