H.P. Lovecraft explained

He was also frightened of invertebrates, marine life in general, temperatures below freezing, fat people, people of other races, race-mixing, slums, percussion instruments, caves, cellars, old age, great expanses of time, monumental architecture, non-Euclidean geometry, deserts, oceans, rats, dogs, the New England countryside, New York City, fungi and molds, viscous substances, medical experiments, dreams, brittle textures, gelatinous textures, the color gray, plant life of diverse sorts, memory lapses, old books, heredity, mists, gases, whistling, whispering—the things that did not frighten him would probably make a shorter list.

Luc Sante, on H.P. Lovecraft.

Now you know what it takes.

(Via William Gibson.)