In a book that I've started reading (and intend to someday finish) the author makes the statement that our future is determined by the choices we make today. While this is true, I also think this can be turned around to the past: the choices we made in the past determine who we are now.
I often find myself thinking "what if I had..." or " I should have..." in regard to my past decisions, but then I remind myself that the way it was was the way it was and there is no going back to do things differently. I know that those choices I made have made me the person I am today and that was/is the way my life was meant to be. With that realization I know that I need to remember that the choices I make today are the ones that determine the future.
A man's heart plans his way, But the Lord directs his steps. Proverbs 16:9