Play Interpersonal Pingpong
If you serve up a smile to people, they usually bounce it back. Hit them with a snarl and watch them scowl instead.
You can use the infectious effects of a grin to jump-start an optimistic outlook in yourself by sending others what you want them to lob back at you. A kind word to the man behind the deli counter can get your day bouncing in the right direction.
— Lise Funderburg, O, The Oprah Magazine contributor