Another Economics Joke

I have a very small collection of economics jokes, not jokes about economics but jokes that teach economics. It just occurred to me that there is another I should add:An economics professor is in a car driven by one of his students; she asks him to put on his seat belt."Why do you want me to put on my seat belt?""To make it less likely that you will be injured in an accident.""Then why don't you take yours off?"I got this one from Allen Sanderson, who teaches introductory economics at Chicago. It may, for all I know, be a true story.