This happiness infographic understands that each person has a different definition of happy but this is how scientists see it. They see it as a combination of how satisfied you are with your life, plus how good you feel on a regular basis. Approximately 40% of your happiness is controlled by your actions, thoughts and behaviors. 10% is determined by circumstances and 50% is is genetically determined.
A few other discoveries made in the happiness infographic are that happy people heal faster after injuries, they volunteer and help others more often, they keep deep friendships and they have experienced some adversity. I personally feel like all these are true. I would consider myself a happy person and this happiness infographic does a great job at breaking down the science behind happiness in an understandable way.