Our happiness is predetermined ~ 50% by genes. This leaves us with a huge opportunity to take action to smile, or want to smile, more often. Overall our brain is like a muscle, the more we influence happiness, the more likely or more easily it can be to attain. You see, happiness is part of a chemical process of neurons and dopamine receptors. If we don’t exercise doing things that enlighten our mood, those receptors can decrease with time and age.