Have you ever wondered?

We all sit back and think about past events, friends we've lost contact with throughout the years, family who has gone and life as we know it today. But, what if we could go back and change the things in the past; the memories we've lost, the friends who we use to be close to, the family we wish we could have spent more time with. What if we have been living in a world that doesn't really exist? What if this is just a view of our future? Would you change things, or would you just let things be as is?