Before completing the initiation process most peoples spirit is plagued by anger, fear, sadness, hatred, despair and vices. Some, after a short time, others a little longer, following the initiation, depending on the person, these feelings are changed; anger is changed by mildness, fear is changed by courage, sadness changed by joy, hatred changed by love, despair changed by hope and vice changed by virtue.
Note that not all types of anger is bad, only criminal anger. Justified anger is good, it is a Godly type of anger." We must be slow to anger". the same with fear and sadness, which can be virtues
Try to always have positive thoughts, keep away from pessimistic attitudes.
According to my medical studies, specially psychoneuroimmunology and psychosomatic medecine emotions can lead to diseases, in chinese medecine, fear affects the kidneys, anger the liver, sadness the lungs, etc... . Any types of stress can change the body's constitution.