"...
- And how do you know that you're mad?
- To begin with, - said the Cat, - a dog's not mad. You grand that?
- I suppose so, - said Alice.
- Well, then, - the Cat went on, - you see, a dog growls when it's angry, and wags its tail when it's pleased. Now I growl when I'm pleased, and wag my tail when I'm angry. Therefore I'm mad."
(c)Lewis Carroll
"Alice's Adventures in Wonderland"