Montag turns to Faber for answers to his questions about his society, brought up by his relationship with Clarisse. He remembers his afternoon in the park with Faber, and knows that he holds the key to understanding why life is the way it is. He asks Faber why books are banned, and what about them makes people so uncomfortable. Faber replies:
They show the pores in the face of life. The comfortable people want only wax moon faces, poreless, hairless, expressionless. We are living in a time when flowers are trying to live on flowers, instead of growing on good rain and black loam. Even fireworks, for all their prettiness, come from the chemistry of the earth. Yet somehow we think we can grow, feeding on flowers and fireworks, without completing the cycle back to reality.
Thus, people fear books because they show the truth of life. They show ugliness and and hurt, death and tragedy. The people in Montag's society have no use for such reminders of the dark side of life. They want happiness and only happiness. Faber understands that this is no way to live, and it goes a long way to explaining why Mildred tries to kill herself.
According to Faber, books are hated and feared because they "show the pores in the face of life." In other words, books do not portray a uniformly positive view of the world: they show every aspect of the world and depict every possible emotion, both good and bad.
Remember that this is a society which tries to suppress anything negative. People are encouraged to watch the parlor walls, to drive fast in their cars, and to focus only on the positive. They are taught to be superficial.
Books, however, do not censor the world in this way. They do not shy away from the truth, no matter how ugly it is.
As Faber points out, people in this society only want "wax moon faces" that are "poreless" and "hairless." They only want to know things which make them happy and to escape the realities of life. But books, by their nature, will never conform to such standards. It is for this reason that Faber says books are hated and feared.