Trying to define yourself is like trying to bite your own teeth.

So one of the things that has been on the forefront of my mind lately is how we define ourselves. Particularly, how we define our lives in terms of our relationships to others. It seems that we are always in a rush to define ourselves in terms of relationship and/or careers. When people ask us who we are we often rush to the obvious choices For example: " I am an accountant" or "I am _______'s girlfriend/wife/ fiance" Do they really define who we are as people? Do these definitions of ourselves somehow make us feel like we are sucessful? Have you ever stopped to think about how many of these types of definitions define you?
Here are mine:
I am Cathe and Garys daughter
I am Toni, Rachel, and Micheles best friend
I am Saras roomate and friend
I am an accountant at a big 4 firm
I am a UD college graduate
I am a woman
I am Brendan's sister
I am from Rochester
I am living in Philadelphia
I am 23
I am Italian and Lithuanian

Why is there such a push to define ourselves in our relation to others? What are your thoughts - & what defines you?