I proposed such a broad question, I appreciate your response. At that, you have provided a great one.
I really do believe the self is constantly being redefined and by doing so, it develops constantly to something new. I happen to like this view and think it is the most healthy way of viewing one self, of course, this is my opinion, however, I really think many issues people face is keeping a static view of one's self.
For example, I used to be a very good runner and could compete with some of the best. But, through injuries and age, I am no longer that person. But, if I kept believing myself to be the athlete I used to be, I would surely be setting myself up for continual disappointment.
I ramble, but your responses really resonate with me.