Smile :)

A stranger was seated next to a little girl on the 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?' and he
smiles.

'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 the same stuff – grass -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, visibly surprised by the little girl's intelligence, thinks
about it and says,
'Hmmm, I have no idea.'

To which the little girl replies, 'Do you really feel qualified to
discuss nuclear power when you don't know shit?'