Our happiness influences the people we know and the people they know.
Research shows that the happiness of a close contact increases the chance of being happy by 15%. The happiness of a 2nd-degree contact (e.g. friend's spouse) by 10% and the happiness of a 3rd-degree contact (e.g. friend of a friend of a friend) by 6%.
When we see someone else smile, we can't help but smile back!
These are triggered by the movements of the muscles in your face, which is interpreted by your brain, which in turn releases these chemicals. Endorphins are responsible for making us feel happy, and they also help lower stress levels. Faking a smile or laugh works as well as the real thing—the brain doesn’t differentiate between real or fake as it interprets the positioning of the facial muscles in the same way. This is known as the facial feedback hypothesis. The more we stimulate our brain to release this chemical the more often we feel happier and relaxed.
Endorphins also act as the body’s natural pain killers. For sufferers of chronic pain, laughing and smiling can be very effective in pain management, as can laughing off the pain when you bump an elbow or fall over.