Another important thing about time is that you cannot stop it. There is no way to slow it down, turn it off, or adjust it. Time marches on. And you cannot bring back time. Once it is gone, it is gone.
Yesterday is lost forever.
If yesterday is lost, tomorrow is uncertain. We may look ahead at a full year's block of time, but we really have no guarantee that we will experience any of it. Obviously, time is one of our most precious possessions. We can waste it. We can worry over it.