Here are mine (might be missing some because I've seen A LOT):
I worked in a medical lab compound around a decade ago. I primarily sorted medical samples and delivered them to the separate labs in the buildings. I kept catching mislabeled and misdirected samples. When I repeatedly looked up who was making the errors, ONE man was REGULARLY the cause for approximately TWO THIRDS of them. When I repeatedly informed management, NOTHING was done. He didn't even receive written reprimands.
I worked at a grocery store where either the front end manager, her assistant, or BOTH were regularly STEALING money from the safe (to my knowledge, they got away with it). There also was a cashier who would call out sick just to go to concerts; another cashier would repeatedly no-call no-show because she "wrote down the wrong hours" and she never bothered to ask for help, just would be like "Oh well, I'm here now".
I worked at the distribution center for some thrift stores and my direct supervisor kept overtly sexually harassing me, which MOST supervisors did to subordinates there.
I worked at a gas station where a coworker stole A LOT of cases of beer by claiming she was picking it up for legitimate work-related reasons (something to do with inventory, not sure why, that the manager was going to do).
I worked at a supermarket/retail store where the woman initially training me was instructing me to go against store policy and CHASE customers suspected of theft, something that according to policy I could get IMMEDIATELY fired for that she did ALL THE TIME.
I worked at a retail store where the store manager would "fix" our timesheets and by that I mean she committed WAGE THEFT.
I worked for a pet store where, instead of giving one employee more hours (who really needed more hours and if they got the hours wouldn't be full-time), they kept hiring inept teenagers who rarely showed up.
I worked at a fast food place (two yellow and conjoined arches) where the store manager took me by my shoulders and SHOOK me because the fries weren't cooking fast enough (this happened when I was 16).
Those are all I can think of for now.