If you want to improve, you can do it in two ways. The first is what everyone does: try something, and then decide whether it was worthwhile based on remembering-self hunches (or skipping the evaluation altogether and calling sour grapes if you failed, sweet grapes if you succeeded). Why, of course it was worthwhile to learn the guitar / compete in a triathlon / have kids / travel the world! And that unfinished movie script, well, it must not have been fulfilling or you would have finished it, right?
