Given a wide enough window we would see that everything is ephemeral. The universe and even time itself will both one day cease to exist.
The most powerful realization I’ve ever had is that the only thing that is forever is love. Love once given can never be taken back. Sure, you can mess things up or grow to hate someone that you once loved, but those memories, those feelings that love granted to you, they will always be there.
It’s a powerful thing. Though we are not gods, and can not create the universe, all of us have the capacity to love and change others forever from their perspective.
One of our simplest and most basic actions can best the universe and time.