Happiness is breathing in the carbon molecules of history. They say that there are still some floating around from the last breaths of the Buddha, Lao Tzu, Jesus, and many other historical figures.
It's waking up everyday with determined outcomes for your life and seeking to reconcile those desires with actual results.
Happiness requires that you never stop learning or give up hope, that you persist onward regardless of hardship. Even in the worst of times, true happiness is the bliss of being alive and understanding what that really means.
So many people don't understand just how special the gift of their consciousness is; the form of mental blocks give way to victimization. It feels good to be pitied and vindicated...until you start feeling weak as a result of the supposed encouragement. Until you realize that your need for pity is damaging your personal integrity by implying that you are unfulfilled in one way or another.
The core of happiness is derived from discovering your personal ambitions and desires. Check out my hub on quality versus quantity here: http://hubpages.com/literature/Quality-versus-Quan... for more insight on these principles.