The classic status of this novel in the haunted house genre kind of mystifies me. I'd not consider it one of Jackson's best, the haunting is rather tepid even by the standards of the time period. The characters are all intensely flakey and suddenly very familiar with each other. Within a day of meeting these four total strangers, they all feel familiar enough with each other to start making the kinds of personality critiques I'd not make until I'd known someone for months at the very shortest. "Always have to be the center of attention," one male character says, intended not unkindly, to the face of a woman he met that week. Predictable, not terribly scary even as a psychological portrait of a person falling apart, and then with a last page "twist" as its climax.
Four unpleasant people go to a haunted house and not much happens and then two more even more unpleasant visitors arrive, so no one in the book is terribly sympathetic.