Smile and laughter are often treated as indicators of happiness as a person cannot make these two expressions unless he is happy.
So what exactly triggers smile or laughter also might trigger happiness. Smile is one of the several expressions or emotions. Many researchers view smile as an expression or feeling of positive emotion. Smiling is a complicated communication tool used by people when they are happy, but the degrees of happiness vary.
Sometimes people put up a pale lifeless smiling expression on face when they are sad. This is also a kind of remembering happiness and understanding they are lacking it at that moment.
Smile is one of the best facial expressions. In old photo studios, it is a religious routine for the photographer to utter 'smile please' before clicking. In Japan, some offices in public service insist their executives always have smile on their face.
Recently marketing departments are using smile features recognition softwares. One such software developed by University of Amsterdam and tested across Europe detects subtle changes in facial muscles. The next question is what causes those subtle changes. Then if you want to be happy you can experiment yourself and initiate such program in your mind.
