Yoga does not look on greed, violence, sloth, excess, pride, lust and fear as ineradicable forms of original sin that exist to wreck our happiness-or indeed on which to found our happiness. They are seen as natural, if unwelcome, manifestations of the human disposition and predicament that are to be solved, not suppressed or denied. Our flawed mechanisms of perception and thought are not a cause for grief (though they bring us grief), but an opportunity to evolve, for an internal evolution of consciousness that will also make possible in a sustainable form our aspirations toward what we call individual success and global progress.
Yoga is the rule book for playing the game of Life, but in this game no one needs to lose. It is tough, and you need to train hard. It requires the willingness to think for yourself, to observe and correct, and to surmount occasional setbacks. It demands honesty, sustained application, and above all love in your heart.
(Excerpt taken from Light on Life by BKS Iyengar)