Having a conversation with someone I talked with regularily as a teen, reminded me of things I said then which only in retrospect show the signs of who I am now. Rereading email from my very first love, that I didn't know I loved romantically, let me see why I was soo very upset when this love loved someone else. Rereading journal entries let me see how I began to realize that things weren't right and the slow process of figuring out what it was that wasn't right.
Retrospect is an interesting way to view things. So much more clear.