Read beefwellingtons SQL EXPLAIN PLAN, comment. I've also watched my roommate have a four hour argument with her coworkers about one line in their kubernetes deployment[0]. I've also spent days trying to fix a declarative Ansible playbook, only to table flip and rewrite it from scratch in 20 minutes (this was a MySQL install-and-configure command where MySQL version had drifted underfoot).

[0] iirc this was not a bug in their kubernetes operator (or maybe it was, I don't recall exactly) but a situation where they didn't understand why their containers were exhibiting the anti affinity properties they were expecting out of their declarations.

edit: were not exhibiting the anti-affinity. They were trying to make sure distributed postgres replica nodes weren't on the same physical hardware, for obvious reasons.