Odd, morbid, ultimately rather depressing example of the statement that "there are no haunted places, only haunted people." In short, it's the sort of psychological horror that I associate with 70s film-making, as a story about a house with an obsessive will of its own turns out to be more about the mental prisons that unhappy people construct for themselves. It really does stick with you, but that's largely because there's such an air of utter sadness to the episode.