Nasruddin's wife complained that she couldn't sleep. "How can anybody sleep with all that loud snoring!" she said.
"I have no idea what you're talking about," Nasruddin replied. "Nothing is disturbing my sleep! But if it will make you feel better, I'll stay awake tonight and investigate."
In the morning he informed his wife of the results. "I didn't hear any snoring," Nasruddin declared. "I stayed awake all night listening, and there wasn't anybody snoring. So, my dear, the only logical conclusion is that you dreamed about someone snoring. To improve your sleep, I'd advise you to dream more softly."
Inspired by: Classic Tales of Mulla Nasreddin retold by Houman Farzad, and translated by Diane Wilcox
Notes: This story is on p. 46 of the book. The Farzad version does not mention the idea of the wife dreaming, but I thought that would work nicely for a punchline.