The best part of this show is not the lack of horror, but the abundance of story telling. Stories that span centuries, back stories for everything and no caricatures or predictable plot twists.
An eerie mood is created by Mike Flanagan from the beginning, where words, cues or incidents stand out in your memory. There is a reason for it all, as the story unfolds.
What you are not prepared for are the surprises the story has in store for you, which explains everything you have seen and a plausible reason for it.
The haunting in this sense stems from grief, heartbreak, torture, abuse and betrayal which leaves a far bigger impact and resonance then traditional scares which are over in the next second.
The show scores for brilliant writing, screen adaptation of the work of Henry James, stellar acting by the cast, especially the younger siblings. Everyone has a story to tell and experiences that have shaped them to be the way they are. Nothing is black and white and no one is bad or good.
The haunting continues to haunt long after it is over.