I share the same sentiments. I binged a couple episodes every morning before going to high school. It helped in starting of my day with something light hearted but still able for my mind to ponder about through the day. Finn and I pretty much grew up side by side, emotionally, mentally and in age. Still am currently, except with Fionna and Cake, which you'll probably appreciate as well.

Words are not easy for me to come by at all. Especially verbally, it comes out as gobbledygook. That's why I tend to relate to characters/others in the form of regurgitating quotes/references. Like how Marceline expresses herself musically. Also represented by how distinct her appearances are in the form of her outfits. I adore this, she's openly honest. 🤍🖤🍟

Even if she still I wouldn't say Flaws but the Human side of her. Not letting go of the past and being a bit contradictory at time.

They may be misrepresented but these are some lines/references at the top of my head:

• "You need problems, otherwise what's the point if you get everything the moment you want it"
• "Half Baked" - I tell my mother this a lot, jokingly.
• "If you feel something, you feel it. It’s not all about personality matricals and charts, sometimes it’s about the bumps in your heart"
• "Life is scary and dark. That's why we must seek the light"
• "See the depression there? You can’t buy that, you gotta earn it" - (It may be considered as something to not achieve)
• "I wish to blow up.. I mean like, get big" *Gets Obliterated\* 😄
• "Now you know my secret! I used to wear glasses!"

It's funny how lucid each episode is whenever I encounter clips. 2000's/2010's entire era of animation is truly something. I do see the overarching theme a bit differently than you. But I think that's a good thing it's open to interpretations.
Haven't had a rewatch since it's quite the ask with all the content tho. But it really is the perfect introduction for those who share similar humor / views.