How long can we look back without tripping on the past?

Lately a lot of people from my past seem to keep popping up everywhere. You've got to wonder if it has a purpose. Are they coming back because something was left undone. . ?. . . or is it just to remind us of who we were and how far we've come from that place. Like a walking photo album.

Sometimes the past can just be comforting. It's familiar. Everyone has that movie that they could watch 100 times regardless of how good or bad the movie is. It's just that we find comfort in the predictability. Do we hang on to the past for comfort?

They say we study history so that we don't repeat the same mistakes. But don't you wish you could just erase some stuff in your past? It's like that movie Eternal Sunshine of the Spotless Mind. . .I know there's a few things I'd erase. And it's not about regret. It's basically about being able to move on. Okay, maybe it's about regret a little bit. . .

Are we always looking back? And if so, are we missing everything that's right in front of us?