The python code we inherited had some performance issues. One of the guys was like "we should rewrite this in Java".

Luckily the boss was not an insane person and shut that down. The issue was an entirely stupid "...and then we do one query per project" behavior that worked fine when the company was small but unsurprisingly started to suck as users created more projects.

Instead of a months long complete rewrite, we had a two hour "let's add profiling... Oh wow that's a lot of queries" session.