The Terrible Truth behind Adventure Time
Yes these are theories that fans have come up with over the years. So i thought it write them out

The Theory: Finn was a lonely boy ignored by everyone but his loyal dog Jake. When Jake dies, Finn falls into a deep depression and attempts suicide. Instead of dying, he ends up a coma, where he lives in a perpetual dream state.

Why it could be true: I DON'T WANT THIS TO BE TRUE! Why is it that fan theories are always so gut-wrenching? This one is courtesy of Creepypasta. Basically all of the stories in Coma Jake's head are ones he used to tell Jake before he died. A fantasy world where he was a hero, princesses loved him and he would remain forever young with his loyal friend Jake by his side. And there he'll remain until he dies. So is Finn's loneliness represented by The Ice King? Awww man my feels can't take it. did this pint of ice cream get in my hands while I sit here snot-crying? Because we havent come to terms with it yet and that it might possibly be true. If you think about it cartoon network normally makes shows that lets kids believe they can do ehat they want. Think about it.

The Theory: The land of Ooo and the adventures of Finn and Jake are really just bedtime stories that Simon Petrikov tells Marceline

Why it could be true: This one comes courtesy of The Theories of Ooo Tumblr page and thepiedmon. Well, Simon was an archaologist, somone who kind of puts together the story of the past, so I can see him being a natural storyteller. Plus as thepiedmon points out, the episodes always involve learning some kind of lesson, so it could be Simon's way of imparting his wisdom to Marceline. I also like the idea that Simon creates the powerful character of the Vampire Queen and an alternate reality to build the confidence of the little street urchin he finds. I really relate to Marceline. The fact that I've also had relationships destroyed after someone ate my fries is only one of the reasons why.

The Theory: Um... that Adventure Time and The Misadventures of Flapjack are taking place int he same universe at the same time.

Why it could be true:
Here's what theory creator, redditor TheNarwhalKing, has to say: "The Misadventures of Flapjack's dock town ( Stormalong Harbor ), is a town built after the mushroom war mentioned in Adventure Time. It is possibly built out of the wreckage of ships that once sailed in that area of the ocean. The area in which Flapjack is set in was not as badly damaged and set back technology wise as Adventure Time is. I also believe that both of these worlds and their strange events are occuring during at about the same time. This would explain cracks within these shows side stories. Such as the main goal of the characters in Flapjack being to get to Candied Island. But unknown to them is that this is not an island but actually a continent, the one where Adventure Time is set. The Candied Island they saw was actually Candy Kingdom. Peppermint Larry has been to Candy Kingdom, and possibly used Princess Bubblegum as a sort of muse to construct his Candy Wife. But Peppermint Larry is not the only character in Flapjack to go to the Candy Kingdom, just the only one who made it back. Phil, in Adventure Time, used to be an inhabitant of Stormalong harbor, until he somehow shipwrecked into the land of Ooo ( Adventure Time ). This is why he is seen in the city of thieves, as he was one of the many crooks and thieves in Stormalong harbor. Adventure Time though, has not many connections within Flapjack because Finn is afraid of the ocean, where Flapjack takes place. If I missed anything or there's a hole in this theory please tell me."

Whoa. Yeah, I kind of don't think you missed anything, Narwhal King. Also thank you for making me feel like a have a smidge of a life. Although I've never come up with an awesome fan you win after all.

The Theory: The stories of Adventure Time are actually Finn and his dad's role-playing computer game.

Why it could be true: Let's all give a shout out to redditor Ayavaron for this awesomely non-sad theory! Here's how he explains it: Jake is really Finn's father and the show is just a D&D game that Jake runs to hang out with his son. Jake is the kind of DM who also keeps a PC there all the time because he can't stand not playing his own game. Mostly he runs the game the way he does because he is always impressed with the strength of Finn's moral core and loves to see that shine even when he puts their characters in tough spots. Ultimately, he always wants to see his son succeed and have fun but he also hopes maybe he can impart some wisdom while they play together.

Awwws! Now I'm going to finish this pint of ice cream as a celebratory act! Don't we all feel better after this one? Except for me in a few hours when I regret my ice cream consumption.

Also comment if you wamt me to add to the list.