According to this quote, it talk about what we've done in the period of time in our lives. While we do things now, sometimes we just make it to the finish. We don't feel anything and don't see the value of it. But don't forget that what had passed, we can’t go back and change it. All the actions in the past, whether good or bad, it is our experience and memories. People will see the value of things, when it has passed. So if there's anything or any event, try to do now. Because it may become our precious memories forever.