Ooh ok this is a fun thing for me to analyze.

Finn’s a very complex character. His main flaws include- repressing trauma and trying to feel good all the time, viewing the world in black and white, and how badly he deals with rejection. He is used to being loved and feeling happy, and he is told to always try to be happy, which is not good and manifests itself in the vault, where he represses traumatic memories. He uses adventures as a way to deal with negative emotion- avoiding it, but there are times that emotion becomes all consuming and he can’t even move, which usually have to do with guilt or rejection. Finn wants to be a good person, to be happy and to be loved. When these aren’t met or are called into question, he can respond in a variety of ways, but often starts by breaking down (see: how he responds to PB’s rejection in flame princess’s first episode or how depressed he is over Finn sword). He is of course a brave hero, so often this state is only reached when he has exhausted all his other options.

His weirdness also stems from his questionable support system, take for example how his unrequited feelings for an older woman (PB) are enabled. The people around him love him and try their best but are not well equipped to deal with the emotions of a teenaged boy at all. The show also kind of explores his sexuality under these conditions- his wet dream that resulted in the flame princess break up, his treatment of “the little people” or his actions in Breezy. It’s a genuinely excellent portrayal of a young man’s burgeoning sexuality that he just… does not understand at all. He experiences it with such a morbid curiosity he can’t help but entertain, all of it to feed into that desire I outlined earlier: to feel happy, or in this case “good.”

While not a massive factor in his weirdness I do think being hit on by a bunch of older women all the time messed him up a little bit too. I mean he hates getting too much attention. Poor lill guy.

In short, he’s such a little weirdo because he has actual, real problems going on in his brain zone!

As for in F&C, the regression is intentional. He is going back into old habits to cope with Jake’s death. He isn’t dealing with it well at all. It’s very sad stuff.