This man was sitting next to a little boy on the plane. Suddenly he turned to the boy and said,

“I’ve heard that flights are going quicker if you talk with a passenger.”

The little boy, who was reading a book, closed it and said to this man,

“What would you like to talk about?”

“I don’t know,” said the man. “What about quantum mechanics?”

“Well,” said the boy.

“That could be interesting. But may I ask you a question?”

The man nodes.

“A horse, a cow, and a deer all eat grass. The same stuff. Yet a deer excretes little pellets, while a cow turns out a flat patty, and a horse produces clumps of dried grass. Why do you suppose that is?”

“I have no any idea.” replied the man.

“Then how is it possible to discuss quantum mechanics when you don’t know shit?”