Nasruddin and his wife lived in a small house and shared a small bed; they had just a single pillow.
One night Nasruddin's head itched so badly that the itchy feeling woke him up. He scratched and scratched, but it didn't do any good. "What an itch!" he thought to himself.
Then his wife yelled, "Stop scratching my head! I'm trying to sleep."
"My apologies, dearest," said Nasruddin. "Go back to sleep."
Nasruddin then felt around until he found his own head.
"Ah," he said to himself, happily scratching the itch. "That explains it. I was scratching the wrong head."
Inspired by: Mulla's Donkey and Other Friends by Mehdi Nakosteen
Notes: This story is on p. 33 of the book.