So many times…
A couple memorable ones:
Once, when I was cashier at a popular clothing store, a female customer came through my line, wanting to pay with a credit card. She did not have her ID on her, and since I had already asked, I couldn't take her card without ID. As she dug through her purse, she said, oh, I do have this!" It was a print out from a plastic surgeon, whom she had seen that day about getting a boob job. It had a picture of them, and her name, she lifted her shirt to show me that they matched.
Another time, after leaving work, and a long day of PITA customers, I stopped at Cold Stone for ice cream. In front of me in the line, was a woman (a Karen for fans of the meme) who was livid that there was not enough Heath bar on her ice cream. The poor girl behind the counter said that there was [whatever the measured amount was], but the last continued her tirade. The girl offered to add some more, but that was not good enough, the b demanded her money back and to speak to the manager. The manager wasn't there, so the girl picked up the phone and started calling, making the lady now pissed off, while the Friday night line got longer. The girl behind the counter was about to cry, and I had been dealing with people like this all day, so I went off on her, and didn't let up until she finally huffed and left. That felt good.