Ego Identity

We all have a ego identity....but everyone's is different based on how we were brought up...how our parents interacted with us as a child until now..I always wondered how some people are so confident regardless of there flaws and how some people are so insecure...to the point when they look in the mirror they see something completely different then everyone else see. thats what made wanna understand why? I realized its our ego identity which is the conscious sense of self that we develop through social interaction.  Its constantly changing due to new experience we inquire daily. so basically its based on what you choose to have take place in your life on the identity you take on for yourself. so does that mean alot of people are insecure because they choose to be? or is it based on things they have gone through that they let impact their sense of thought? idk....something im interested in looking into to understand the whole concept. I feel with determination and focus even a person with the worse insecurities can make a change for the better if they have strong minded people in their life to help them see the good in them instead of all the negative and with time that person will transform into a very confident happy person! just what I believe.