Swami Vivekananda stressed on the positive attitudes of life- love, harmony, service and the like. Some of these concepts find echo in an emerging trend of psychological studies called Positive Psychology. In fact, most of these traits are considered as marks of spiritual wisdom.
Desire, want, is the father of all misery. Desires are bound by the laws of success and failure. Desires must bring misery. The great secret of true success, of true happiness, is this: the person who asks for no return, the perfectly unselfish person, is the most successful.
-Swami Vivekananda