I realize that most other blog posts that link to this all-too-short examination of personal fave H.P. Lovecraft in the New York Review of Books are quoting this paragraph, but it really is one of the best things ever written about Howard:

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.

The article essentially makes the case that Lovecraft was the penultimate nerd, to which all of us who have been fans of his over the years answer with a resounding “Well, DUH!”
Much like Rick Moranis’ character in Ghostbusters, only hardcore nerds can open up gates to otherworldly realms as expansive and horrifying as Lovecraft’s. The extroverted and socially popular couldn’t be counted on to catch a glimpse of eldritch horrors or understand the inherent creepiness of non-Euclidean geometry if the fate of the world depended upon it.