Light bulb

A doctor of psychology at the insane asylum was doing his normal morning rounds when he entered a patient's room. He
found Patient #1 sitting on the floor, pretending to saw a piece of wood in half. Patient #2 was hanging from the ceiling, by his feet. The doctor asked patient #1 what he was doing.
The patient replied, "Can't you see I'm sawing this piece of wood in half?"

The doctor inquired of Patient #1 what Patient #2 was doing.
Patient #1 replied, "Oh. He's my friend, but he's a little crazy. He thinks he's a light bulb."

The doctor looks up and notices Patient #2's face is flushing red. The doctor asks Patient #1, "If he's your friend, you should get him down from there before he hurts himself"
Patient #1 replies, "What? And work in the dark?"