When I was about half way through this novel, I was worried that it was turning into another tale of the manic pixie dream girl. For those of you that are not familiar with this damaging trope, here's a quick crash course: http://tvtropes.org/pmwiki/pmwiki.php/Main/ManicPixieDreamGirl. And if you really don't care to read it, I will summarize the summary: An MPDG is a quirky woman who brings adventure into the life of a depressive man and (most importantly) has no independent goals of her own - she purely exists to change him and often disappears when she does. In short, it's a flat character, a lazy plot device, and a disappointing, limited view of females as a whole.
But wait! I had faith in John Green and thankfully he knew how dangerous that trope was and in many ways this seemed to be his response to the dangers of the male gaze. Yes, Margo is quirky (not a bad or unrealistic thing) and she does change Q's life (again, a good thing). But he does add a complexity to Margo and an introspection and awareness to Q that is very refreshing. All characters are flawed, dynamic people that can be both selfish and care for others.
I loved the mystery, humor, and realistic high school friendships that John Green has proven to be so great at writing. I highly recommend this for a spring read, and then you can go see the movie this summer!