Read Chesterton's essay The Nightmare.
That is, I fancy, the true doctrine on the subject of Tales of Terror and such things, which unless a man of letters do well and truly believe, without doubt he will end by blowing his brains out or by writing badly. Man, the central pillar of the world must be upright and straight; around him all the trees and beasts and elements and devils may crook and curl like smoke if they choose. All really imaginative literature is only the contrast between the weird curves of Nature and the straightness of the soul. Man may behold what ugliness he likes if he is sure that he will not worship it; but there are some so weak that they will worship a thing only because it is ugly. These must be chained to the beautiful. It is not always wrong even to go, like Dante, to the brink of the lowest promontory and look down at hell. It is when you look up at hell that a serious miscalculation has probably been made.