An Alcoholic, a Chain Smoker and a Homosexual go to the doctor. 

The doctor says: "If any of you indulge one more time you'll die."

As they walk home they pass a bar. The Alcoholic has a shot of whiskey, falls off his stool stone cold dead. His friends are shocked.

As they walk along they come upon a cigarette butt lying on the ground still burning.

The Homosexual looks at the Chain Smoker and says: "If you bend over to pick that up, we're both dead!"