Happiness is acknowledged and generated with a smile.
Our usual outward expression when we are happy is a smile, and smiling at someone transfers some of our feel-good moods to the recipient of our smile. The recipients' response is generally to acknowledge our smile with a smile of their own. Science calls this a symbiotic relationship, and it triggers the release of dopamine, endorphins, and serotonin in our brains. These hormones are a large part of our reward system; they make us feel good and encourage us to seek more of that feeling. Even a feigned or forced smile reduces stress and makes us happier.
Psychologists have found that the more pleasing feelings we experience daily, not their intensity, are a good predictor of our happiness. So, smile away and share your smile frequently with others!