Two strangers are sitting in adjacent seats in airplane. One guy says
to the other, "Let's talk. I hear that the flight will go faster if
you strike up a conversation with your fellow passenger."

The other guy, who had just opened a good book, closes it slowly,
takes off his glasses and asks, "What would you like to discuss?"

The first guy says, "Oh, I don't know; how about Nuclear Power?"

The other guy says, "OK, that could make for some pretty interesting
conversation. But let me ask you a question first: A horse, a cow,
and a deer all eat the same stuff, but the deer excretes pellets; the
cow, big patties; and the horse, clumps of dried grass. Why is that?"

The first guy says, "I don't know."

The other guy says, "Oh? Well then, do you really think you're
qualified to discuss Nuclear Power when you don't know shit?"