A man opens an outdoor stand to sell bagels and puts up a sign, "50 cents each." A jogger runs past and puts 50 cents into the bucket but doesn't take a bagel. The next day, he does the same thing. For weeks and then months, this goes on.

One day, as he's jogging past, the owner joins him. The jogger laughs and says, "I know why you're here. You want to know why I always put money in the bucket and never take a bagel?"

"No," says the owner, "not that. I just want to tell you that the bagels have gone up to 60 cents."