A bad habit
I overheard a friend telling his pal, "I can't break my wife of the habit of staying up until 5 in the morning.""What is she doing?", the pal asks."Waiting for me to get home."

Bad temper problem
Patient: Doctor, you must help me. I'm under such a lot of stress, I keep losing my temper with people.

Doctor: Tell me about your problem.

Patient: I just did, didn't I, you stupid fool!!