Actually, I think they have just as much impact. By nature we're beings that dwell on our greatest regrets, and for relationships that never develop to the fullness and (in some cases) grandeur that we assign it in our minds there is always that lingering "what if" or "damn me to hell, what the hell is wrong with me?!?". We all have them, we all let them affect one or another. You'd have to be lacking a pulse to say you haven't had at least one in your life. And so it goes...