I did find Amber Appleton kind of . . . let's go with "grating." But not because she was "optimistic," as we're repeatedly told. It was because she was a damaged kid with serious daddy/boundary issues, and there was very little acknowledgement of that in the story. That, and she used a lot of Amber-specific language and catchphrases and abbreviations that take longer to say than the original phrase.
Which isn't to say I disliked her. I mean, I rarely found her quite as annoying as I think she is. God help me, I'd probably have been friends with her in high school (if she had any female friends at all, that is—which she doesn't, because she surrounds herself with light-on-spine boys who'll do anything she tells them to, and then gets overly familiar with every adult male not packing Mace).
In all, though, it was a decent read, and a not unfaithful portrayal of a certain type of teen-age girl. I'd just been promised hopefulness, and instead, for example, there's a scene where she's supposed to defeat an elderly nihilist with her youthful optimism, and her entire offense consists of jokes about how old and decrepit her opponent is. Whaaaa? And stop saying "True? True." all the damn time!
Anyway. When I'm an elderly nihilist, I doubt I'll even have the energy to tell girls like her they have a dinosaur face. What can you do.