A dark and disturbing story of sibling rivalry, All You Never Wanted is unlike any contemporary I've ever read. Both protagonists have their own issues - one is a pathological liar while the other is literally wasting away to nothing because of her anxiety - yet those issues pale in comparison to the underlying jealousy motivating every action. With an overnight romance and a vaguely abrupt ending though, All You Never Wanted left me wanting more.Thea is Alex's younger sister, tired of living in her shadow. Having decided to re-imagine herself in her inner popular self's image, someone she calls Gia, she's desperate to fit in. And that means becoming best friends with Alex's friends, a group she calls the Blondes, and secretly coveting Alex's boyfriend, Jason. Thea's storyline in All You Never Wanted was enough to capture my attention, as her imagination was constantly in overdrive, working on a new story that might help her to become a part of the popular crowd.This story is nasty and everyone is spelbound and that's power. They're all hooked and I'm in focus, I'm mixing up this thing like I'm the smoothest bartender in the newest club for people who've all decided at this moment I'm one of them. And if there's guilt down my spine, it's nothing like the heat on my skin as I raise my voice to land it. Likes take nerve, which I'm working on. But nobody needs to know that.She wasn't above making up a lie in order to become the center of attention, and she had no concern for the consequences; she fully believed she'd be able to talk herself out of any situation with another lie.While watching Thea descend into desperation, we also had to endure Alex's anxiety-ridden neurosis, which at times, was completely debilitating. Having experienced something traumatizing during a summer internship, Alex has become a shell of the person she once was. Fearful of losing control over her body, she limits what she eats/drinks to the point of developing what seems to be an eating disorder. She has distanced herself from both her friends and family (leaving room for Thea to weasel her way into their lives) and has days where she's unable to pull her car out of the driveway.With such compelling backstories, All You Never Wanted had me completely hooked. But as Thea's lies became more outrageous and she became more desperate to replace Alex, my concern for her mental health increased to the point where I had to wonder if she would have been clinically diagnosed with some sort of psychosis - and why none of her friends/family thought the same and thought to seek out professional help. And because of the extreme reaction Alex showed to her traumatizing event, I was convinced something extremely damaging had to have happened to her. When the details surrounding the event unfolded, I was left feeling...underwhelmed? What happened would definitely have been mortifying, but I can't imagine it affecting my life as drastically as it affected Alex's.Towards the end, I loved watching Alex begin to recapture control and live her life again, but I was annoyed that she needed a guy to help her find herself. My annoyance was only strengthened by Alex and Xander's instant romance. Their relationship was so sudden and out-of-the-blue, that I was left wondering if I had missed a chapter. Alex's entire outlook on her life was completely changed by one interaction, and with Xander at her side, it was like her traumatizing event had never happened. And after only one day together, Alex was talking about possibly being in love with Xander! I just wasn't buying it. Add in the completely vague ending, where Thea tells Alex a secret that we're never privy to, and I was left quite disappointed after All You Never Wanted's potential-filled beginning.With absolutely no resolution for Thea, and something that might be seen as running away from her problems for Alex, All You Never Wanted really came up short in the end. I love that Griffin didn't try to tie everything up in a nice bow, but some resolution is necessary so I don't feel like I've wasted my time. But a really well-done, though complicated, relationship between sisters and a writing style that I enjoyed did make All You Never Wanted a mostly entertaining read.