I'm in a mood....

A stranger was seated next to a little girl on an airplane when the stranger turned to her and said,"Let's talk. I've heard that flights go quicker if you strike up a conversation with your fellow passenger."The little girl, who had just opened her book, closed it slowly and said to the stranger, "What would you like to talk about?""Oh, I don't know," said the stranger, how about nuclear power?""OK.", she said, "That could be an interesting topic. But let me ask you a question first:
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?"The stranger thinks about it and says, "Hmmm, I have no idea.""Do you actually feel qualified to discuss nuclear power, when you don't know shit?", says the girl as she goes back to reading her book.