An expression of happiness is often expressed through a SMILE. A SMILE is a facial expression that is formed by flexing the muscles near both ends of the mouth. It is usually associated with pleasure, joy, or amusement. A smileononesface is a more intense expression of happiness, which is characterized by a broadening of the mouth and eyes, and an increase in the size of the cheeks. This expression is often seen when someone is feeling particularly joyful or content.