My best was at the Grand Californian at DL. We were sitting at the pool and had just ordered a beverage. A guy a few feet away had just started yelling at a CM because his beverage did not arrive in a quick enough fashion to suit him, even though the pool was very crowded, and the CMs were extremely busy. He talked about how he had been in the service industry forever, and that the service he was getting totally sucked, and that it shouldn't take so long to get a beverage. She tried to explain that they were busy, but he didn't care. HIS needs should come first before other people since he had paid so much (like everyone else was staying there for free). He continued ranting for 10 minutes at this poor girl, and then finally physically threatened her if he didn't get his drink like now. We could NOT believe this idiot. We went to the CM manager and pointed him out, told her a few things he had said, and security was there inside 30 seconds escorting him away. The poor girl was in tears at this point, and we talked with her to calm her down.
We found out later from the CM manager (who comped all of our drinks that afternoon!) that the jerk was actually kicked out of the hotel, and told not to come back! Karma was rally working that day!