I used to work in a sub shop in high school. The only customer whose memory linger with me as an asshole was the guy who came in 10 minutes before close, wanted a grilled sub (one that takes fifteen minutes) and then was pissed we were out of the bread he wanted. Like dude, it's closing time, did you expect we'd be fully stocked? My manager was in the back counting one of the drawers, and I was "acting" manager on the floor (I had worked there the longest), so when he starts getting pissy with the new girl I stepped in. The guy wants a discount for waiting so long (which I explain we can't give him, because the sub meat needs to be cooked for a specific time), changes his mind after the girl rings him up because he suddenly wants a cookie, which makes it a combo, then is pissed when it means we'd have to wait for the manager to void the transaction. He just did everything with a look that was angry, yet smug. I couldn't fix what was put in the register without a managers thumbprint, so then he starts yelling. It would have been 30 cents difference, and it's now 9:10 pm. We're all going to get dinged for clocking out late due to a late close. He's still ranting about how we're bad at our jobs and the girl next to me is starting to tear up, so I give him 30 cents from the drawer and tell him to have a nice night. Thankfully he left, with another glare and something something. I followed him to the door and locked it behind him, where he told me I was stupid and not going to go anywhere in life, and how our entire store sucked. I told my manager about the drawer being thirty cents short now and lucky for me, she wasn't mad because I was honest, and I was good at my job and took money from my wallet to make it even.