A guy discovered that he had a flat tire and pulled to the curb. He realized that he had stopped in front of the local mental health sanitarium when a patient ambled up to the fence and began teasing him.
He ignored the patient's catcalls and insults while he carefully took each lug nut off and placed it in the hubcap as he removed the tire. While trying to install the spare, he inadvertently knocked the hubcap, which spilled the lugs and all five nuts fell into the nearby storm sewer, falling beyond his reach.
The patient howled with laughter as the guy, at the end of his patience, began to vent about being stuck there until a tow truck could arrive. The patient told him, "I can help you."
The guy glared at him and said, "Sure you can."
The patient said, "No, really, I can help."
The guy reluctantly asked how. The deranged patient then said, "Take one nut off of the other three tires and put the spare on with three lugs. Then you can safely drive to a garage for the other nuts and get your tire fixed."
The guy thanked him and asked, "How did a guy like you ever think that one up?"
To which the asylum patient replied, "Well, I'm just crazy, not stupid!"