Defining the "I"

Tonight, my question is not "What defines you," but rather "What do you let define you?"
Is it your hobby? Your sport? The things you do with your hands or mind? Do you live in the moments of these uniquenesses, surround yourself by like-minded people in a community where you feel most like yourself? Does this become who you are and want to be?
Or, is it what others say? Have you created a bubble or built up a pretense of being someone else? ... a person you admired or started to become so long ago, you don't remember who decided to change?-- the 'old' you. Do you see yourself as beautiful, smart, ignorant, or outcast because that's what you hear?
What do you allow to become your definition? And most importantly, is this 'ok' with you?