What is Self Esteem and Confidence?:

Self Esteem is the opinion you hold about and your worth. Having high self esteem means you feel good about yourself as a person and hold realistic and positive expectations about what you can achieve. 
Why is it important to have high self esteem?
Having high self esteem means that you are more likely to be happy with the person you are. It allows you to live your life to your full potential and feel good about yourself in both social and non social situations (it is important to feel good about yourself 24/7, not just when you are with friends!) 

Having high self esteem means that you can be confident - knowing that you have the ability to succeed, and not being afraid to fail.