Originally Posted by Dvandemon
I think that Pen also said no one realizes it. But even if they did, what's there to be sad about? There's evil but there's heroes too, and we can tell that Ooo is pretty awesome even with all the monsters.
Mushroom war was bad, but hey. No one was left who could remember how it had happened, at least, no-one who would do anything.
Or so Dr. Wily believed.
Marceline, some business men in ice. Maybe a few others outside the afterlife and the nightosphere. But it's been a long time since, long enough for baseline humanity to nearly go extinct, wars to be fought, and a lot of other stuff went down.
The present is pretty sweet. There's a cure for death.