By confining your child to blameless stories of child life in which nothing at all alarming ever happened, you would fail to banish the terrors, and would succeed in banishing all that can ennoble them or make them endurable. For in the fairy tales, side by side with the terrible figures, we find the immemorial comforters and protectors, the radiant ones; and the terrible figures are not merely terrible, but sublime.
It would be nice if no little boy in bed, hearing or thinking he hears, a sound, were ever at all frightened. But if he is going to be frightened, I think it better that he should think of giants and dragons than merely of burglars. And I think St. George, or any bright champion in armour, is a better comfort than the idea of police.
—CS Lewis, On Three Ways of Writing for Children