If a person cannot smile or laugh freely, in all probability he or she is not a happy person. There is link between smile/laugh, positive emotions and ability to move facial muscles. Look into mirror every day. Try how many facial muscles you can move using the very muscles but not hand or any other tool to lift.
If you cannot move many face muscles, you cannot smile happily. As you cannot smile happily, there is an underlying cause at your emotional world. There must be something wrong there. In fact, this link is found in a study of Botox, which actually paralyses the muscles in the area. The purpose is to cure wrinkles. But the side effect is that you cannot show up emotions.
Facial expressions act as feed back mechanism to the brain. So, keep smiling and avoid frowning.
