I was reading a treatise of a Muslim Saint and he came up with a brilliant idea that if you think good about others you feel good about yourself as if you are in a state of sublime intoxication. This happens cause you free yourself from wanting anything from others. This freedom allows your brain to stimulate those particles in your brain cells which make you happy. Remember like happiness , sadness and depression are also created situation. All these may have external triggers but that should be absorbed like springs in a fast moving vehicle which may feel a bounce but recovers from the jump soon...