Don't ever become a pessimist... a pessimist is correct oftener than an optimist, but an optimist has more fun, and neither can stop the march of events.
Happiness lies in being privileged to work hard for long hours in doing whatever you think is worth doing. One man may find happiness in supporting a wife and children. Another may find it in robbing banks. Still another may labor mightily for years in pursuing pure research with no discernible result. Note the individual and subjective nature of each case. No two are alike and there is no reason to expect them to be. Each man or woman must find for himself or herself that occupation in which hard work and long hours make him or her happy.
First you must learn to control your self. The rest follows. Blessed is he who knows himself and commands himself, for the world is his and love and happiness and peace walk with him wherever he goes.