One of my favorite sayings is Walk Fast and Smile! The "Smile" part of that equation suggests that you can change your mood by consciously smiling; you can affect the mood (positively) of those around you by smiling; and that you generally will feel better if you smile.
There is evidence that Learning to Laugh at Yourself Builds Self Esteem.
There are lots of theories about the health benefits of laughter or smiling.
I recently found a website that included quotations about laughter ... here are three of my favorites from that site:
>A sense of humor is good for you. Have you ever heard of a laughing hyena with heartburn? ... Bob Hope
>Laughter is an instant vacation! ... Milton Berle
>Laughter is part of the human survival kit ... David Nathan
So ... what does it take to convince people that they should be smiling?
Start now ... SMILE, LAUGH and truly enjoy your life!