The Mental Patient
Morgan is driving past the Mental Hospital when his right rear tire suffers a flat. While he is changing the tire, another car goes by, running over the hub cap in which he was keeping the lug nuts. The nuts are all knocked into a nearby storm drain.
He is at a loss for what to do and is about to go call a taxi when he hears a shout from behind the hospital guardrail, where one of the patients has been watching the whole thing.
“Hey, mate! Why don’t you just take one lug nut off each of the other three wheels and use them to replace the missing ones? That’ll hold your tires on until you can get to a garage or something.”
Morgan is amazed by the patient’s seeming rationality, but he understands the plan will work, and installs the spare tire without incident. Before he leaves, he calls back to the patient. “You know, that was pretty sharp thinking. Why do they have you in there?”
The patient smiles and says, “I’m in here because I’m crazy, not because I’m stupid.”