adventure time slang is weird cuz like. when you first watch the show and hear the slang you're like "oh this is cringy slang but its not like awful" but it gets to a point where the voice actors deliver the slang so naturally you don't even notice it and its just. part of the world's vernacular. I can't think of any other show that's done in-universe slang like this
Finn: oh man the frappin dude just ginked up and went flipoo over the junkin fence
Me, 3 seasons into this show: wow he really did huh