Did you know that it only takes seventeen face muscles to smile and, in contrast, a whopping forty-three muscles for your mouth to go the other way?
Other positive thoughts:
Tis easy enough to be pleasant, When life flows along like a song; But the man’s worth while is the one who is smiling when everything goes dead wrong. — Ella Wheeler Wilcox
Smile and others will smile back. Smile to show how transparent, how candid you are. Smile if you have nothing to say. Most of all, do not hide the fact you have nothing to say nor your total indifference to others. Let this emptiness, this profound indifference shine out spontaneously in your smile. — Jean Baudrillard
The world is like a mirror, you see? Smile, and your friends smile back. –Japanese Zen saying