Emotions are one’s immediate response during interactions with the external world like joy, fear, anger lust etc. Emotions are, in fact, essential for one to survive. But it does not mean that emotions of all kinds and strengths always help one to survive. The emotions that help one to survive a situation can turn dangerous in a different situation. The capacity of one’s inner self to regulate these highly relative emotions naturally in the right way decides whether one should lead a ‘calm and pleasant life’ or not.
Practice it and make it a habit. Then the nature will make it sustainable by triggering necessary genetic engineering!