Smiling is a natural response that shares our happiness with others. Smiling also triggers activity in our brain. According to sources, there's a serious  mind-body connection in our left frontal cortex to be exact, which is the area of our brain that registers  happiness. How often do we smile in a day? We smile when we meet new people, when we see our friends and other significant situations. Our face has 44 muscles in it that allows us to make more than 5,000 different types of expressions, many of which are smiles. Say cheese!