I really liked this book. It was a well-paced, quick read. It definitely resonated with me, because I was a teenager who struggled with suicidal ideation for years. 
 Reading through other reviews, I am stunned by the number of people commenting and saying Hannah's reasons for committing suicide were "trivial." You are all missing the point. 
 Hannah, as portrayed, is severely depressed. 
 She does not see the world the same way mentally healthy people do. Events do not look the same to her or feel the same to her as they do to you. I know, because I was a depressed teenager who almost committed suicide over nothing. Seriously. Nothing. I was homeschooled; I never got bullied. The world just looked huge and overwhelming and terrifying to me because I was not a mentally healthy person. It had very little to do with what was going on in the outside world, and almost everything to do with what was going on inside my head. 
 Even so, there were triggering events. I overheard my grandmother complaining that I was irresponsible because I'd forgotten to do a chore. To a mentally healthy person's ears, that's "Great, she's annoyed, I'd better remember next time." To my depressed ears, it meant that I was worthless and would never, ever be good enough, and that I had lost the love and respect of everyone that mattered to me. I barely managed to talk myself out of suicide that day. 
 Now I'm in my 20s. I'm not depressed anymore. I've finished college. I'm happy and well-adjusted. But it still chills me to the bone when I see people talking ignorantly and dismissively about a character with mental illness, and failing to see how mental illnesses change the way you perceive and react to the world. 
 The fact that people commit suicide for reasons that aren't "good enough" does not for a second make it okay to dismiss the reality of their pain. We should all be looking for warning signs, all the time. Even in people who haven't experienced severe trauma. Because that isn't how mental illness works; it doesn't require severe trauma. We should all remember that we can't really know the mental state of the people we're interacting with, and as much as is in our power, avoid cruel acts--even ones that seem small to us--which might serve as the last straw. 
 Sometimes, there aren't any reasons at all, just illness and a broken mind. That doesn't make any suicidal person's pain any less real, or their life any less valuable. Just because they don't have "valid reasons" doesn't make them not worth fighting for.