I've been thinking about season five and how it's been showing an uglier side of Finn. All the Little People and Frost & Fire are obvious examples of this, but after some thought, I realized that this has been steadily building since the very beginning. We're all used to Finn being a pretty good kid who tries to do the right thing, but all along, there have been little hints that he has some of the tendancies of a spoiled brat, tendancies that have gotten stronger as he's aged and not had to really deal with the consequences of his actions.
This shows all the way back in Slumber Party Panic, when Finn breaks a Royal Promise. Yes, he thought it didn't really apply anymore, so it wasn't a malicious action, but he still did something wrong. The only consequence for this was that he had to answer a simple math question. And as he himself pointed out, there were a lot of cool consequences to it as well. He didn't learn anything except that he could get away with doing stuff because he's a well liked hero.
In Prisoners of Love, Finn starts out the episode joyfully breaking the law. He's trespassed on the land of another kingdom to selfishly alleviate his own boredom and to get away from the heat of the lava man hanging out around the Tree Fort. When confronted by the rightful ruler of the Ice Kingdom and with his breaking of Ice Kingdom law, he sulks and essentially says that Ice King wouldn't care if his laws were broken if he wasn't an uncool nerd. Ice King is well within his rights to capture and incarcerate Finn. The princesses, however, are another matter. Finn's law breaking leads to him rescuing the princesses and being hailed as a hero. He learns only that there are no negative consequences to doing whatever he wants to do.
In The Chamber of Frozen Blades, Finn and Jake break into Ice King's home in the belief that he has princesses there. This is not bad or selfish behavior, but while they're there, they start destroying things because they want to have fun with some of Ice King's belongings. When confronted with what they've done, Finn does momentarily feel bad, but once they discover that Ice King actually has kidnapped someone, Finn seems to feel justified in what he's done. He gets to beat up Ice King and rescue Doctor Princess with no negative consequences for what he did.
In Another Way, Finn seems to learn the value of other people having their own way of doing things, but if you think about it, he was able to fix all of the damage he did by continuing to do things his own way. There were no lasting consequences for anyone (except the cyclops) for his selfish "MY WAY!" behavior. He failed to learn that while everyone has the right to have their own way of doing things, sometimes that way is just plain wrong sometimes.
In All the Little People, Finn really gets into manipulating people. He completely ruins the lives of most of the Little People, and even then, the Little Person he's most concerned about is Little Finn. He feels bad about what he did, but again, there are no lasting consequences because he's able to use words to set everything right.
In Jakesuit, Finn selfishly uses Jake's body, assuming that since it doesn't bother him to be hurt, it shouldn't bother anyone else. Instead of apologizing or feeling bad, he just tells Jake to deal with and enjoy the pain. After Jake takes over Finn's body, he finally gives in and says Finn is right, not because he really believes it, but because he doesn't want to cause Finn the pain of a lava dunking. In response to this, Finn jumps them both into lava, with Jake's body on the outside, taking the most damage. The only real consequences of this for Finn are having to deal with the Clown Nurses again.
Then we have Frost and Fire, were Finn tries to talk his way out of the mess he made, like in All the Little People. He honestly expects this to work, which is why he says "but I said sorry" at the end, as if that should have made everything instantly better. He's finally having to deal with the consequences of his actions and to realize that he can't have everything the way he wants it just because he's a well-liked hero. And that maybe that well-like part isn't going to stay if he doesn't get his act together.
There were several other episodes in past seasons that highlighted some of his bad behaviors (Princess Monster Wife, Guardians of Sunshine, Death in Bloom, and several others), but I didn't want this to get too long (Everyone who bothered to read this far: "Too late!"). Any other thoughts on this, or episodes where Finn has acted in selfish/negative ways without really learning anything?