The foe of happiness is not malicious people or frustrating circumstances. It is a sly enemy unseen by millions of its victims. The cunning foe is your own unseen reactions. You are unaware of your hundreds of daily mechanical reactions, and so remain under their pounding punishment. If you knew you were hurting yourself with useless guilt or envy would you allow them? Never. So make your reactions conscious, which changes them from punishing to pleasing.