Ugh. I was so on board with this until the end. So literally the only way that she can stop Juliet from committing suicide is to sacrifice herself? And big ole meanie Sam deserves to die so much more than Juliet because...? I don't know, but after spending all this time with Sam and getting to see her make positive changes in her life, I think it's a total cop-out to make her not have to follow through with these changes. What's the point in teaching her all these things about herself if she doesn't have to change, not really? Her friends won't get the chance to change with her - because she's dead. And surely Juliet is now going to shoulder the blame for Sam's death, thus making her inherent problems even worse - I'd be pretty pissed off if my best friend died trying to save you because you ran out in front of a car. ARGH.
Also it's just plain stupid that there was no other way to prevent Juliet dying. And why was this Sam's responsibility anyway? I'm always reminded of that scene in Buffy, in the episode Earshot, where Jonathan's going to kill himself:JONATHAN: Stop saying my name like we're friends! We're not friends! You all think I'm an idiot! A short idiot!
BUFFY: I don't. I don't think about you much at all. Nobody here really does. Bugs you, doesn't it. You have all this pain, and all these feelings and nobody's really paying attention.
JONATHAN: You think I just want attention?
BUFFY: No. I think you're up in the clock tower with a high-powered rifle because you wanna blend in. Believe it or not, Jonathan, I understand about the pain.
JONATHAN: Oh right. Because the burden of being beautiful and athletic, that's a crippler.
BUFFY: You know what? I was wrong. You are an idiot. My life happens to, on occasion, suck beyond the telling of it. Sometimes more than I can handle. And it's not just mine. Every single person down there is ignoring your pain because they're too busy with their own.The beautiful ones. The popular ones. The guys that pick on you. Everyone. If you could hear what they were feeling. The loneliness. The confusion. It looks quiet down there. It's not. It's deafening
In short, well written and characterised book let down by the worst ending I could have imagined the author giving it. I'm not pissed off because the ending was sad - I'm pissed off because the ending was morally horrible and rendered the preceding 465 pages completely pointless.