I’ve never in my 13 or so years in this industry seen even the most disgruntled person leave anything in an intentionally broken state. Broken due to incompetence though? Plenty.
I got laid off while working to fix a nasty bug that kept crashing our servers. I never finished or checked in that code, and the corpus of discovery leading to the solution was all ephemeral on my machine, so when I wiped said machine, it went up in smoke.
I wasn't deliberately sabotaging anything, and had I been given more notice than a morning video meeting with the office manager before my access was cut, I'd have probably checked in at least my WIP with a good commit message. But I wasn't, so I didn't
Yeah, I've seen people get fired and it actually lessened the amount of work those around them had to do. There's people out there in big and small companies, doing negative work every day.
I wasn't deliberately sabotaging anything, and had I been given more notice than a morning video meeting with the office manager before my access was cut, I'd have probably checked in at least my WIP with a good commit message. But I wasn't, so I didn't