With just a simple search I found 10 health benefits to smiling! Now I won't list them all, a few I found especially intriguing are; lowered blood pressure, released serotonin and a natural pain reliever, boosts your immune system, and my personal favorite, it's contagious. Without saying a single word you can pass all these benefits to another person, even a stranger, talk about a quick fix. I found all this information on about.com, written by Dr. Mark Stibich. Even the notable LiveStrong campaign has written about this topic (http://www.livestrong.com/article/18859-health-benefits-smiling/) listing some of the same benefits as the article mentioned above.
So to quote Mcdonald's commercial slogan from the 90's "Put a smile on, put a smile on, everybody come on! And put a smile on!"