If we fail to control them, many emotions will not fail to leave their impact on us. As a result of all these, our body loses its normalcy. This changed state subjects our body to various illnesses. Man suffers from asthma, blood pressure, ulcer etc. Many diseases are the result of mental stress.
Emotions originate from body.
However its original cause, the thought, originate in the mind. The thought belongs to you as no other person can enter your head. Therefore you should be careful about the thoughts which enter your head. We can modify those thoughts, choose the good ones and admit the noble ones. Unless we want, no one can inject any thought into our mind and if we really want, then, no one can prevent it either.