When you feel your past was mostly wasted, and that you didn't live as much as you wish you had, you feel rather bad, like you have lost something that you will never get back. But let's see how that goes with a great past. You regret that it's gone, because you'll never get it back either. Different pasts, similar results. So basically, whatever kind of past you have, it makes you sad. Although, you can see it from a different angle: my past sucked, and I am glad it's over with. Does that work? You tell me. Personally, I find that everything in my past makes me sad, whether it was sad, because it was sad, or good, because it's over. There seems to be no escape from being sad about the past. Except maybe to simply look ahead.