A stranger was seated next to Joe on a plane. “Let’s talk,” he said to the guy. “I’ve heard that flights go a lot quicker if you can strike up a conversation with a fellow passenger.”

Closing the book he’d been reading, Joe looked at the man and said, “Okay. So what would you like to discuss?”

“Oh, I don’t know,” said the stranger with a shrug. “How about nuclear power?”

“That would be an interesting topic, but let me ask you a question first,” Joe said. “Horses, cows, and deer all eat grass. Yet deer excrete little pellets, cows turn out flat patties, and horses produce clumps of dried grass. Why do you suppose that is?”

“You’ve got me there,” the stranger laughed. “I have no idea.”

“Well, then,” said Joe, “how is it you feel qualified to discuss nuclear power when you don’t know shit?”