In order to be happy one must have an end which is infinite and in which the journey is enjoyable. By that I mean that you have to have a goal which you are striving for, a goal in which you can take pleasure in trying to achieve and not just in the achievement. I think that is true happiness, the pursuit of a noble end. True happiness is devoting yourself to something intrinsically rewarding.
Therefore true sorrow is to find yourself without purpose. Lost in a sea of opportunities, looking for something to want.
True pain is wanting something you can’t have.
The road of life is a long, unpaved, overgrown path. The key to satisfaction is learning to enjoy the walk.