I care because there's something in my life I would really like to explain by comparing it to the relationship in that book. I never get to have this conversation.
The book is so good and so different and observes some really interesting human shit. Please read it. It's not even that long.
*This is why I say books read before age twenty do not count. What you remember at all will have been through the lens of someone who did not have enough life experience to have understood anything, or at least not enough. With the possible exception of To Kill a Mockingbird.