My nickname growing up was "Mouse"...

Because I was so shy, so insecure, I was afraid to use my own voice. This carried on into my adult years and that insecurity stopped me from doing so many things that I wanted to do. 

I would look at people who were confident and think "If only I could be like them".

Then I learned that confidence is something that can be learned. It's a behaviour and when you understand how behaviour works unconsciously, you can adopt any behaviour you want.