"Back to my original point," he said, "I don't believe in ghosts. But I do think places, like this motel room, I think they hold on to bad things, the way people hold on to memories. Grief. Pain. Disease. Addiction. I think when you enter a place that's absorbed enough bad things, it pukes them out at you. It drenches you in them. So a relatively innocuous room, like this one, will appear evil. Because bad things happened here."
very reminiscent of "The Shining" that whole bad places are haunted by the bad things that happened there idea.