Back when we were first introduced to Vriska she was at an odd position. She was as evil as ever, but she had problems that suggested somebody who had a hard outer shell of being full of themself and kind of a huge bitch but had a scared confused little girl inside they never wanted to address. She had flaws that made her tragic, and while I hated her evil nature I accepted that she could become a character I could eventually emphasize with.
When you sit down and really think about it (and I just spent 30 minutes doing so), it all falls into place, not just for Vriska but for basically all the characters. It's easy to forget that these character's are not complete people and just traits and dialogue on a page, created by a veteran comic writer, who prides himself on writing the story on the fly (and leave it to Vriska to wind up being Hussie's mouthpiece about herself). So easy in fact that I willfully do so, because dissecting these characters as if this were an historical narrative is just too much fun.
Suspending disbelief and taking Vriska at her word (and there's no reason not to), it really is easy to piece together that scared little girl under all that bitchiness. At heart, she wants to have friends, and she wants to be liked by her friends and support them in turn. But her whole life she was raised to the vicious understanding of Trolldom and her place in it - that being conniving, hateful, duplicitous, and vengeful are virtues. "Friends" becomes "people to make and break alliances with", "being liked" becomes "being respected, or better feared", "support" becomes "brutalize into improvement". Oh and while you're at it, keep Shelob fed and happy. She likes Trollmeat.
Vriska's not without her character flaws obviously. She's impulsive and rash, she needs to at least
tell herself that she feels good about herself, she's addicting, and she doesn't know how to back down. Her everyday existence is roleplaying a persona, of a capricious bitch who epitomizes the Trolling virtues to the point of freaking out her compatriots with her drive. But she doesn't really know how to take the mask off, she's addicted to the validation. Meanwhile she wants to reconcile the inescapable need to do right by her friends, through only the painful definitions of "right" and "friend" she knows. And that little girl inside keeps getting more afraid of what she knows she's doing compared to what she can't wholly understand she wants to be.
She snapped. She gave up and gave in to the learned need to be what she thinks she's supposed to be, and the result - the permanent death of someone she cared about, and never knew how to explain herself to - finally shocked into wholly recognizing what she wants. She had godhood handed to her, like almost every other advantage she's enjoyed, but none of that substituted for real maturity - maturing not into a Troll ideal, but what she really is.
Vriska's not alone in that dichotomy. All twelve of them are "weird" for their world, but it's worth thinking about who's the weird ones. Troll society encourages wanton self-interested brutality, and the Trolls that came off most as antisocial maniacs were Vriska, Eridan, Equius, and Karkat. Equius is operating a lot like Vriska, but with his own creepy problems getting in the way of recognizing himself. He learned different life lessons from the pressure of what lessons were imposed on him, fixated on the "state" of Troll rather than the "action". But under all his aristocratic douchebaggery, it was easy to see a guy who just wanted to set all the complications aside and be friendly and helpful, he just hemmed in by too many codes and barriers to express it right. Pity he was truly and ultimately a joke character, since he'll never be explored much.
Eridan is somewhere between the two. He's buried under the weight of expectation and proper form dumped on him by Trolldom, and trying his best to live up to everything his status is supposed to entail, and the ideals of a legacy and birthright he straight up admits he imagined for himself. He wants his enemies to fear him and his objects of affection to adore him, and to hear the lamentations at his reign of terror and destruction, and look back on a swath of burning victory and proclaim his dominion. But it's all ultimately just a need to feel respected and needed, like anyone wants to be, and live up to the sea-rulers, the only people he thinks he's allowed to call his peers. And he has his own simple flaws of course, rash impulse and an unrequited ego more than anything; he acts without thinking and can barely admit to himself when he's wrong. But for all we know, after obliterating the woman he could never have and the one person who put up with him more than anyone and any chance at rebuilding his world, all just to prove he was right about all hope being lost, and
ensuring it in the process, he could be bawling his nictitating eyes out in the wandpile right now after he's had time to cool down.
The clearest example of all of course is Karkat. From his introduction through every page afterwards, it was painfully obvious that KK was not the Adonis of trolldom he made himself out to be, and he knew it and everyone else knew it. He's a lot like Vriska really, an ultimately nice guy who wants to help his friends and prove himself. But it's filtered through his regimented understanding of what it means to "be" a Troll. He can't slaughter his contemporaries for their weaknesses, he has to force them to be something more. Vriska picked up on the blunt metaphor of his blood instantly, he's basically a "human" trapped in a Troll, and doing his best to deny or reconcile it. He's painfully obsessed with being "normal" - normal house, normal movies, normal games, normal-and-more aspirations, and most of all a brutally
normal disdain for all things weak and disruptive to his image of what he's supposed to be. Extending to his obsession with mastering, and proving such, the "normal" Troll relationships. And since his spiel to Vriska about the nature of hatred, I always suspected that half of what Karkat knew about Troll society was invented propaganda by a warrior empire, and the other half was Karkat's own cockamamie understanding of such. And of course, his manic quest to be Troll Beaver Cleaver wouldn't be complete if it wasn't utterly transparent to everyone around him. Any time that veneer falls apart and Karkat's forced to be himself, he seems almost relieved, or at least settled.
While the obsession with normalcy doesn't run through all the Trolls, they're all kinda wracked with a friendly core of being, that their brutal utilitarian society never taught them how to really express or act on. They have a blessing and a curse in the "Morailegience", but the formal nature of the relationship keeps them from fully acknowledging friendships outside of it. And of course, we've all seen the friendship-center thing at work in the Kids from day 1. I'd even say that the dynamic of "gung ho adoption of a stultifying upbringing while subconsciously trying to escape it" paralleled Rose and Dave's bizarre family lives; Vriska et al. more or less embraced a society where Dave's freaky upbringing is cranked to eleven and played for keeps every day, with exile (and death) awaiting anyone who can't cut it.
EDIT: Good gog almihgtey that is a big wall of text. I think I need to go to sleep.