I admit that twice two makes four is an excellent thing, but if we are to give everything its due, twice two makes five is sometimes a very charming thing too.
After you've done a thing the same way for two years, look it over carefully. After five years, look at it with suspicion. And after ten years, throw it away and start all over.
Man is the only animal that laughs and weeps; for he is the only animal that is struck with the difference between what things are, and what they ought to be.