According to this article and a few pieces of research that it points to, we should smile more. Kids smile about 400 times a day. Adults smile on average only 20 times a day. This is a great straight to the point article about something we often forget to do. And anyone who smiles often is not only naturally happier, but also much healthier.
He points to a British study that shows that smiling has a profound effect on the reward part of the brain: One smile is worth the sort of brain activation that 2,000 chocolate bars might elicit (insert dubious eyebrow-raising here). It can also help reduce stress-inducing hormones like adrenalin and cortisol (which can seriously mess with your sleep patterns) and increase mood-enhancing hormones like endorphins, not to mention reducing overall blood pressure.
Consider the following data from Intelligent Life Magazine concerning the smile’s twin sister, laughter: 11 percent of laughter is a result of joke-telling; 17 percent is from media (Weiner’s weiner, LOL cats, YouTube, etc.) and a whopping 72 percent arises spontaneously from social interaction.
Kids Smile 400 Times a Day: What about Adults? (Parentables)