Thinking about the positive things in your life, and appreciating what you actually have (relationships and things) makes people happy.
“Happiness and unhappiness are certainly related, but they are not actually opposites. Images of the brain show that parts of the left cerebral cortex are more active than the right when we are experiencing happiness, while the right side becomes more active when we are unhappy.”
Read more: http://www.nytimes.com/2014/07/20/opinion/sunday/arthur-c-brooks-love-people-not-pleasure.html?_r=0