Without it, life on Earth probably never would have occurred. It has defended life on Earth from many meteor and asteroid strikes. It energizes life on Earth today. It may even save us from ourselves with its gift of massive amounts of free energy, ours for the taking. "It" is our moon.
This BBC documentary, Do We Really Need the Moon, is brilliant, almost mesmerizing. It's almost an hour in length but it only takes a few minutes' watching before you'll be hooked.