Patient: “Doctor, do you think that I shall live until I am ninety?”
Doctor: “How old are you now?”
Patient: “Forty. “
Doctor: “Do you drink, gamble, smoke or do you have any other vice?”
Patient: “No. I don’t drink. I don’t gamble. I don’t smoke. I have no vice. “
Doctor: “Then why do you want to live for another fifty years?”
This joke is included in the Black Book of Jokes. You can order it from here.