The fact that they mention using EMACS makes it even funnier

Reminds me when I was working with a guy and he named a database table recieved . I had adapted my code to that, and then one day without warning he renamed it to received - and it took us an hour to figure out why everything broke.

Excel wrongly assuming the year 1900 was a leap year for their timestamps is my favorite bug that will never be fixed because everyone has built workarounds for this already

I wrote code for industrial automation years ago (think assembly line machines). I was reviewing production code and found a stupid bug and fixed it, then reinstalled. The motors moved incorrectly - I don't recall if that was the time it smashed glass everywhere, but "fixing" the code definitely broke the program. I could not figure out why...but due to time constraints I sadly had reinsert the bug to put the machine back in production.

Some nights that still bothers me.