"Make it a whisky," said the man who promptly throws it down in one gulp.
"That will be three dollars," said the bartender.
"Says you!" said the man. "You offered to get me something. I thought you were paying."
"Get out," said the bartender. "You're banned. I don't need your business."
Anyway, two years later, the same man went back to the same bar with the same bartender.
The bartender looked at him and said, "You're the jerk who tried to con a drink out of me, aren't you?"
"Excuse me, but I have no idea what you are talking about," said the customer. "I've never been to this bar before in my life!"
"Sorry. My mistake," said the bartender. "You must have a double."
"Hey thanks, dude!" said the customer. "Make it a whisky."