A congressman was seated next to a little girl on an airplane. He turned to her and said, "Do you want to talk? Flights go quicker if you strike up a conversation with your fellow passenger."
The little girl, who had just started to read her book, replied to this total stranger, "What would you want to talk about?"
"Oh, I don't know," said the congressman. "How about global warming, universal healthcare or economic stimulus packages?" He smiled smugly.
"Okay," she said. "Those could be interesting topics, but let me ask you a question first. A horse, a cow and a deer all eat the same stuff--grass. Yet a deer excretes little pellets, a cow turns out a flat patty, and a horse produces clumps. Why do you suppose that is?"
The legislator, visibly surprised by the little girl's intelligence, thinks about it a few seconds and says, "Hmmm, I have no idea."
To which the little girl replies, "Do you really feel qualified to discuss global warming, universal healthcare or the economy when you don't know shit?"
And then she went back to reading her book.