"Bad Idea" joke

A friend of mine (Dave) told me this story over the summer,
and swore up and down that it's true (he says he witnessed it).
It sounds a little far-fetched, but is amusing nonetheless.
Here's the story:
Dave was standing in the parking lot of a 7-11 store when this
guy walked out of the store with a six pack (of beer he assumed)
in a brown paper sack. The guy walked between two cars and when
he did, the bag lightly touched one of the cars. As it turned
out, a guy and his girlfriend were sitting in the car, and the
boyfriend (trying to impress his girlfriend) got out of the car
and started bitching at this beer-guy for scratching his car. So
the beer-guy apologized but the boyfriend kept on ranting.
After a while, the beer-guy said, "If it'll make you feel any
better, go over and kick a few dents in my truck" and pointed to a
beat up pickup truck across the parking lot.
So the boyfriend
went over and started kicking the door of the truck in when
another guy walked out of the store and screamed, "What are you
doing to my truck???"
The boyfriend said, "That guy over there
told me that this was his truck" and when he turned around to
look at the beer-guy, he saw him driving off in his car.