"Quitters, Inc." is a short story by Stephen King which was published as a part of his book, Night Shift. It concerns a man named Dick Morrison who wants to quit smoking. He bumps into an old friend, Jim McCann, who tells him that a place called Quitters, Inc. helped him to quit. Dick goes to Quitters, who tell him they have a 98% success rate. After Dick signs up, he finds out why. Quitters, Inc. has found out everything about him, including who his family and friends are. They have a series of threats against Dick's loved ones that they say they will carry out if Dick smokes. Quitters lists very specific, horrible things they will do to Dick or his family, including electric shocks, and breaking his son's arms. If he is caught smoking a tenth time, his Quitter's counselor tells him he will be killed--these are the 2% that are failures for Quitters, Inc. Dick doesn't really believe either that they would harm his wife, disabled son, or Dick himself, or that they could possibly find out if he does break down and smoke. He is wrong, and is forced to watch his wife Lucinda receive half an hour of electric shocks. She understands, though, that he is trying to quit, and supports his efforts. After Dick gains some weight due to his success with stopping smoking, he finds that Quitters considers all of his bad habits part of their contract with him and will cut off one of his wife's fingers if he doesn't lose weight. Dick loses weight. Much later, he runs into Jim (who originally set Dick up with Quitters) and Jim's wife--who is missing a finger.
This is one of my favorite King short stories! He shows that sometimes when people think they can't stop a bad habit, they have perhaps just not had a strong enough incentive to quit.