Have you ever looked back on bad memories to take a moment to enjoy the fact that they happened to you? Doesn't matter what it was, a memory is a memory, and every one of them is a part of you, for better or for worse. The present and future are important, but never let their importance allow you to forget that where you came from is important as well. Bad, good, either way, it's all still you, for as long as you exist anyway. Though, I guess if you dislike yourself or the way you turned out, this advice isn't quite applicable...meh.