When I worked in a call center back in the late 90s, I knew agents who would suspend peoples service if they pissed them off during a call (This was before the system could track who was in the acct during the calls, and before they could record the interaction on the computer as well) so they would always get a way with it lol
I worked for a catering company and we had a very rude Mother of the bride. Who ended up calling and getting a full refund let alone not tipping. I sent her a pee pee glitter
When I worked at a restaurant. I use to give smaller portions to rude customers.
I was horrible as a teen. When customers were rude, I would lick their straw before I stuck it in their drink.
Back in the early 2000s, I used to cut only the edges of the pizzas when customers were rude. Try and eat that a-hole
When I worked at a plasma center, if a patient was being a jerk I would make one of there pre-donation numbers off. Like the protein level had to be a certain number and I'd move it just right to read too low or high so they couldn't donate
Had a coworker who put a large credit onto his own acct for working at the company after we were taught how to do this for customers. needless to say he got a call the next day and POOF fired; but they never removed the credit and just left it there on his account lo
I worked for the restaurant industry for about ten years. And would get passively aggressive with rude customers. When they would ask ten times for ranch/sauce before I even left to go get it, I would bring back ten or more things or sauce then proceed to ask if that would be enough. I would at Einstein and had a regular who just was picky, extremely hard sandwich and would watch you make it and If you did one thing even kinda wrong she would yell at you. We got rid of the machine she liked called a press (grilled the bread) and I made sure to throw it out while she was in line :) she didn't come as often after that.
Worked at a restaurant would save the utensils that were still dirty after the dishwasher and stick it in their food
Work at a bar.. a guy tossed his credit card at me.. I ran his payment and threw it back at him. He didn't tip but it was worth it.