4. Princess Bubblegum & Marceline dated (and that was OK)
The past relationship between female characters Princess Bubblegum and Marceline is a major highlight of episodes such as Season 3 Episode 10 "What Was Missing" (where we learn hints of their history) and Season 7 Episode 2 "Varmints" (where they seem to begin reconnecting).
The significance of having a (or at least alluding to a past) same-sex relationship represented in a mainstream cartoon is obvious. Over the past eight years though, I began to worry that Adventure Time walked a line between respecting their relationship by not radicalising it, but then also disrespecting queer viewers by.
But as a hetero this is not for me to say. And then, of course, there's the finale (keeping this article spoiler-free!). I can only hope that after their hundreds of years coexisting in the Land of Ooo, and after 10 seasons following the events of the finale, PB and Marcy have their happy ending. Just like that dream Marceline had once (although minus the vampires this time).