And how do you know that you're mad?

"To begin with," said the Cat, "a dog's not mad. You grant that?" I suppose so, said Alice. "Well then," the Cat went on, "you see a dog growls when it's angry, and wags it's tale when it's pleased. Now I growl when I'm pleased, and wag my tail when I'm angry. Therefore I'm mad.

~Lewis Carroll, Alice's Adventures in Wonderland & Through the Looking-Glass

It is cool for cats...