Though it is a tragic love story, it is also a perfect and irresistible fantasy. Hazel and Gus possess an absolute moral authority, an ability to assert the truth of their experience that few can share and many might covet. They know the meaning of their own lives, and try as it might, the movie can’t help but give cancer credit for this state of perfection. There is something disturbing about that, and also, therefore, about the source of some of the tears the movie calls forth. The loudest weeping you hear — including your own — may arise not from grief or admiration, but from envy.