Actually, I thought this movie was pretty accurate.
And I could relate to it nearly 90%. She was a bit extreme in some parts, like I'd never cause a scene like that in public, but I have thrown things out of anger at my first boyfriend.
I'm pretty sure Ricci's Elizabeth was well-aware she was despicable. That's the point. That's why she hates herself. Which makes her act that way, which makes her hate herself... it's a vicious cycle.
This film was pretty creepy for me to watch, it was like looking at my adolescence all over again. Goddamn. What pained me the most wasn't the internal *beep* Elizabeth was going through, but the damage she was causing those around her. Especially her mother, who was not without flaws, but boy did she have patience.
Maybe this movie's only for the egocentric types of depressed people to relate to, or whatever we can be called. But it does happen, and it does suck, and yes, we know we're horrible people when it happens. But mirroring our aggression and telling us we're horrible isn't going to change things. To be honest, I don't know what will. I'm only 23 now, but for me, I just stuck it through and eventually starting changing on my own, through more painful relationships and self-reflection and just life in general. I can still look back on this film and understand/remember how bad it was before, but I'm definitely a more patient and understanding person now who's pulled her head out of her ass at least a little of the way. It's a process.
Sorry for the tl;dr.