I have a perfect story for this thread that just happened a few hours ago!
In work earlier tonight, I was standing at the top of the stairs leading to my office in wait because I recognized a voice from downstairs. The voice belonged to a customer who comes shopping every night with his wife. The wife is friendly and awesome and I like talking to her, but the husband is a major pain in everyone's butt. So I was just hiding upstairs, enjoying my drink, and listening to his story about their dinner that they just came from.
The man didn't tip a server because the server only brought them two bread sticks.
He ranted and raved about his lack of bread sticks for twenty minutes. He absolutely hated that server for not bringing him three more bread sticks, and then this man blamed his wife for eating all the bread sticks. Ugh.
Actually, a lot of the customers in my store are easily offended. If one customer brushes up against another, there's usually a string of swears screamed through the entire store as the two customers get into a fight. Or some customers want to ban children under the age of 18 and their parents from ever entering the store.