happiness for me is a state of mind... yes, a condition by which a person knows that he or she is secure and is contented with what is already there. In a way, one could decide whether or not he is happy.
Relatively though, it could be analyzed that somehow, this state of mind is defined by the being of the person. It depends on how he prioritize matters and deal with challenges in life that would likely determine his happiness.
I do think that being happy in the middle of a stressful world is a possibility that everyone could embrace.
I would like to share one of the hubs I wrote in connection to this matter,
The Pursuit of Happiness: the Desire for Wealth Vs the Desire for Contentment
found at http://hubpages.com/health/The-Pursuit-of-Happines...
Hope this helps :)