Who you are depends on the stories you tell yourself. Identity shapes beliefs and vice versa. Beliefs drive behaviors. Behaviors predict results.
Crafting your self-narrative is an ongoing process. You have, at any given time, the ability to change your self-perception. Your interpretation of the events in your life determines who you are. Who you were is old news; who you are and yet to be is a gift that keeps on giving. Nothing has meaning until you assign meaning to it. A pen is a pen because someone in the past called it that and enough people followed suit. Thankfully, you don't need a big enough group of people to believe who you say you are. Who you believe you are is the foundation of self-mastery. It's the foundation of outstanding leadership. It is only when a leader is certain about himself that he is able to look outwards and lead his people. So with each challenge (and victory) that comes your way, ask yourself, Who am I? What would someone like me do in this situation?