Moviegoers aren't happy with mother!, but not necessarily because they think it's bad.

Writer/director Darren Aronofsky's latest earned an F from CinemaScore. It's rare to see such a low grade from the Las Vegas-based audience polling firm, but when it does happen it's usually because of a marketing fail rather than a creative fail (though sometimes it is just because a movie is that bad).

In the case of mother!, as Mashable's Angie Han has already pointed out, it's not the "haunted house horror" that trailers suggest. In actuality, it's much "stranger and more ambitious."

Unfortunately for mother!, there's little room for nuance in CinemaScore grading. A 2016 interview in the Las Vegas Review-Journal with Ed Mintz, the firm's founder, clarifies what the letter grades generally equate to for a new movie's overall quality and business outlook.

"A’s generally are good, B’s generally are shaky, and C’s are terrible," he explained. "D’s and F’s, they shouldn’t have made the movie, or they promoted it funny and the absolute wrong crowd got into it."

That latter point is likely the case with mother!, which has gotten a largely positive reception from critics. As Angie wrote in her review:

"Some people will come away bowled over by its ambitions and artistry. Many will be annoyed to discover it's not the film the trailer is selling. Still others will react with ambivalence. All of those people will leave the theater wanting to talk about it afterward."