You are not childish for wishing the world was better than it is. We were owed that by the people who knew better before us, just like we too will owe the people who’ll come after us. But defeatism does nothing. It puts nothing on the plate you’ll hand to your child, your friend, your lover. You may never live to see the world become as good as it should, but that should never stop you from trying to improve it anyway.