Harry is getting along in years and finds that he is unable to perform in bed. He finally goes to his doctor who tries a few things, but nothing seems to work. So the doctor refers him to an American Indian medicine man.

The medicine man says, "I can cure this." That said, he throws a white powder in a flame, and there is a flash with billowing blue smoke.

Then he says, "This is powerful medicine. You can only use it once a year. All you have to do is say '123'"

The guy then asks, "What happens when I want the effect to go away."

The medicine man replies: "All you or your partner has to say is 1234. But be warned - it will not work again for another year."

Harry rushes home, eager to try out his new powers.

That night he is ready to surprise Joyce. He showers, shaves, and puts on his best shaving lotion. He gets into bed, and lying next to her says, "123." It works better than he thought.

Joyce, who had been facing away, turns over and asks, "What did you say 123 for?"

And now you know why you shouldn't end a sentence with a preposition