Joe had been drinking at the bar for hours when he mentioned something about his girlfriend being out in the car.
The bartender, concerned because it was so cold, went to check on her. When he looked inside the car, he saw Joe's buddy, Mark, and the girlfriend kissing in the back seat. The bartender shook his head and walked back inside. He told Joe that he thought it might be a good idea to check on his girlfriend.
Joe staggered outside to the car, saw Mark and his girlfriend kissing, then walked back into the bar, laughing.
"What's so funny?" the bartender asked.
"That darned Mark!" Joe chortled. "He's so drunk, he thinks he's me!"