WOW SO MANY SPOILERS GUYS
I love Adventure Time. I remember watching the pilot years ago and enjoying it. It took me a lot longer to start watching the show (it had about 4 seasons by the time I started watching it) but after the first season it got so good. Not that it was bad during the first season, the show was just good at ramping up.
Adventure Time is about a boy named Finn and his best bro, a dog named Jake with magical powers. They live in the Land of Ooo, where they operate as kind of professional superheroes. One interesting aspect of the show is that as the show progresses, the story becomes darker and darker, usually kind of in the background, but sometimes just right up in your face.
For example, the main bad guy in the series is The Lich, who just straight up kills people. He doesn’t joke around. You later find out that the Land of Ooo is a post-apocalyptic civilization that emerged following a horrific nuclear war, and that the Lich was born out of the ferocious weapons unleashed there.
The contrast between the light-hearted adventures of two carefree heroes, and the horrific darkness of the past, makes for a really interesting show. The show is also really good at developing the backstories of characters who you could at first write off, like the Ice King, the first villain of the series. Originally he was villainous but eventually just kind of evolves into a nuisance and then you discover his origin where once the Ice King was a heroic survivor of the apocalyptic war, struggling, very much in Cormac McCarthy’s The Road style, to survive and protect a child he finds along the way. The horrible price he pays to protect the child is what leads him down the path to being the Ice King.
So I recommend Adventure Time. Each episode is only like 10 minutes, which makes watching it a pretty low pressure thing. Definitely watch two seasons if you start because, as I said, the show seriously picks up after that.