Motorist and the Asylum Patient

A motorist had a flat tire in front of an insane asylum. He took the wheel off, and the bolts that held on the wheel rolled into the sewer. A patient, looking through the fence, suggested that the man take one bolt from the remaining three wheels to hold the fourth wheel in place until he could get to a service station.
The motorist thanked him profusely and said, "I don't know why you are in that place." The patient said, "I'm here for being crazy, not for being stupid."