The Mexican place in question has a special on Sundays where if you order a drink, you get tacos for 69 cents. A few friends and I had gone there on a Sunday and we all ordered tacos. There were signs on the table that said that gratuity would be added to the bill for groups of 8 or more. There were 7 of us and another on the way, and I asked our waiter if the gratuity would be added even if we didn't get a single check.
I rarely eat out in large groups, so I didn't know. It may or may not have been a stupid question... but his answer was downright rude. He went, "Oh, so you don't want to tip me?!"
First of all, nice attempt to make me look cheap in front of my friends. Second of all, way to not know what "gratuity" means.
When he came back with our food, he gave everybody else their orders first. When there was one plate left, he said, "I guess this must be yours" and handed it to me. As it turned out, not only were those tacos not the ones I'd ordered (they were all beef and I'd asked for chicken, beef and chili con carne), but they weren't even the right NUMBER of tacos.
I didn't feel like tipping by the end, but I was paying debit and the debit machine was at the servers' station. He stood right next to me while I paid.