be glad the moon is a solo satellite.
what if it had a sibling?
there would be lunar rivalry, for sure, and an interesting planetary/solar system dynamic.
they would argue between themselves about which one the earth liked best. the one with the closest orbit to the earth would say it was the favorite. the other one would ask if it was sure about that.
the bigger moon would think that it was the most important one because of its size. but it could be jealous of the smaller moon.
they might throw bits of themselves at each other. that would be a spectacular show for humans.
or they might bump into each other's orbits. that would throw them off kilter, and fly off into the depths of the universe.