Something that I find interesting about Loki- at least my reading of him in the films- is that he DOES (or did) have the potential to...make better choices, to be a good guy, to be that sympathetic character who gets handed shit but overcomes it. But what makes him specifically interesting to me is that he makes such deliberate choices to be a villain. It's not "woobie, destroyer of worlds" (in tvtropes parlance), the kind of menace who really, if someone had given him a hug, maybe he woudn't be trying to commit genocide. He's funny, charismatic, and clever. He could do better. But he doesn't want to.

I mean, another trend you see in fanfic with him is to give him this hugely tragic backstory, where he's abused and abused and abused- as to justify things, or to make him even more woobieish- but there's so little of that evident in the movies. Odin was kind of a dick, yeah. But in what we actually see, Loki has't had a hard childhood or anything, his jealousy is revealed to be just that, and just that irrational. (That is, he starts out maybe having an argument about Thor, but the movie quickly reveals how much that's simply an excuse).

There's a really interesting reversal and exploration of some of this in Journey into Mystery, which READITREADITREADITREADIT. Ahem. Which really underlines the degree to which it wasn't circumstances that made Loki (albeit comics Loki, in this case) who he was, it was his choices. (which of course means he could choose differently.)