Hill house watches. Hill House waits.
-- Narrator (Prologue)

Importance: The prologue establishes Hill House as the novel's primary antagonist. Even before the characters convene in the setting, the house has menacing and nefarious intentions. By placing these descriptive lines at the forefront of the novel, the author locates the narrative conflict in the house, and thus foreshadows its negative impact on the characters.

When you're confronted with something deeply strange or obviously implausible in a book or movie or painting, you know it means something.
-- Narrator (chapter 4)

Importance: Holly chooses to ignore the warning signs she sees when she first discovers Hill House. She knows that inexplicable sightings and events in literature have symbolic, ominous resonances. However, she struggles to apply this knowledge to her lived experience. This moment establishes Holly's avoidant tendencies and her desire to control her reality via logic.

Luck had brought me here, I decided, luck or fate or some other impulse...
-- Narrator (chapter 9)