The most important part of understanding the book is trying to make sense of the seemingly random freak accident at the end, when just as Jamal goes to steal the family BMW, that's when Quy is hiding to surprise his family. Jamal panics and beats him and might even have killed him—he didn't care. He stole the car, and that was his objective. But accidentally, he damaged one of the families in his community by ruining an already long-expected reunion. Although Jamal doesn't think through the reality of other people's lives, that doesn't mean they are immune to him.
Jamal ruins Quy's life by welcoming him to town with violence and horror. Why would Jamal do that to someone? Isn't Jamal's life hard enough that he can empathize with those who suffer like Quy? The answer is that Jamal has allowed his victimhood to give him the license to do whatever he wants, and then, his untreated mental issues, alongside his history of violence and hatred, push him to do things that are unspeakably cruel and violent.
The purpose of the novel seems to be that instead of pulling our communities apart through violence, that we should be encouraging one another toward happier healthier lives. Although it might seem perfectly disconnected, Tuyen faces these same temptations, but they aren't urging her to do violence; they push her to become unstable in one of her friendships and to disapprove of Binh, but is it really that different?
Ultimately, the novel is a picture of pain and suffering, but not for no reason. The hope of the characters is the same as the hope the readers have for them—that the pain and suffering of their past would not shape their futures, but when one uses victimhood as license to hurt others, the book points to that as a crucial failure.
