Building a healthy self esteem can do wonders for your life. The way you deal with people on a personal and professional level are all affected by how you perceive yourself. Having a low level of self confidence may greatly affect your life; you end up having a harder time performing at work, maintaining healthy relationships, and enjoying life.
When I was little I was unsure about everything and fretted about anything. If the cat was sick. If my teacher wasn't on form. If my parents were unhappy. Sometimes I would come away from talking to someone who was negatively charged and feel inexplicably down. They would say something slightly critical and I would feel annihilated.