Alex Mandossian posted something very interesting to his blog entitled "What is Your Verb?" that I think is a very good exercise for us all.
What is your verb? What is it that you do that defines your very essence? For example, for Rene Descartes it was "I think, therefore I am."
Alex's is "I improve, therefore I am."
Mine is "I write, therefore I am."
What is your verb? According to Alex, if you change your verb you change your whole life.