Mathematics is the language in which God has written the universe.
Courtesy costs nothing. Lower the toilet seat after use. Let the people in the elevator exit before you enter. Return shopping carts to their designated areas. When you borrow something， return it better shape (filled up， cleaned) than when you got it.
"The world is a mirror, and the mirror is a lie."
Never compromise on quality—your brand is only as strong as your weakest product.
The concept of a legal system presupposes the concept of a rule.