One of the things Ford Prefect had always found hardest to understand about humans was their habit of continually stating the obvious… At first Ford formed a theory to account for this human behaviour. If human beings don’t keep exercising their lips, he thought, their mouths seize up. After a few months’ consideration and observation he abandoned this theory in favour of a new one. If they don’t keep on excercising their lips, he thought, their brains start working.

One of my favorite passages from the Hitchhiker’s Guide to the Galaxy.