Anger comes from unrealistic expectations of reality. The Bhagavad-gita explains how we are all trying to take the position of being the Supreme controller in this world. We try to control situations, control people, and control the objects around us. When we fail, we become frustrated and angry. Everyone boils at different degrees, but one who has unrealistic expectations in life will repeatedly face the problem of anger.
All that is available at our disposal is our best efforts. Living a spiritual life means we try our best and simultaneously understand that there are factors involved beyond our control. An experienced monk once told me, “if you want to make God laugh then just tell him your plans!” Acting free of anger ensures that all actions in life are performed with the clarity of spiritual intelligence, and thus we can avoid all the physiological, emotional and societal ramifications of this destructive emotion.