why you shouldn't end a sentence with a preposition

Harry was getting along in years and found that he was unable to perform sexually. He finally went to his doctor, who tried a few things but nothing seemed to work. So the doctor referred him to an American Indian medicine man.

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

Then he said, "This is powerful medicine. You can only use it once a year. All you have to do is say '123' and it shall rise for as long as you wish!"

Harry then asked, "What happens when it's over, and I don't want to continue?"

The medicine man replied: "All you or your partner have to say is '1234,' and it will go down. But be warned -- it will not work again for another year!'

Harry rushed home, eager to try out his new powers and prowess.

That night he was ready to surprise his wife, so he showered, shaved, and put on his most exotic shaving lotion. He got into bed, and lying next to her said, "123." He suddenly became more aroused than anytime in his life ... just as the medicine man had promised.

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

And that, my friends, is why you shouldn't end a sentence with a preposition.