"We can use our minds and imaginations in either a wholesome or a degraded way; by the same token, human beings can produce good fantasy or bad fantasy. Both draw on the inner world of the soul, and both can be a way of making spiritual realities tangible, presenting goodness and evil in concrete terms. Good fantasy elevates and disciplines the imagination, awakening its readers to the beauty of goodness as well as to the repulsiveness of evil . . . Good fantasy projects a universe of grandeur and meaning. Good and evil are a matter of moral absolutes. Th principles of virtue are austere and all-demanding, yet full of splendor. Evil is presented in all of its hideousness. The reader's moral sensibility is sharpened, and spiritual truth is thrown into high relief.
Bad fantasy, on the other hand, is concerned only with the self. The writers of much contemporary fantasy are doing nothing more than manufacturing daydreams for the reader. In line with the demands of mass culture, they are designed solely for self-gratification and often do little to elevate or instruct the imagination."
Quote from Reading Between the Lines: A Christian Guide to Literature, by Gene Edward Veith, Jr.