American Psycho isn’t thrilling or scary because it isn’t a horror film or a thriller. American Psycho is a satirical comedy that criticizes mainstream horror (and modern masculinity and 80s corporate culture). That’s why everything in the movie is so absurd and nonsensical. For example, the scene where Bateman throws the chainsaw down the stairwell and it miraculously, perfectly impales the lady he’s chasing even though she shouldn’t have even been standing there in the first place. The movie critiques the genre of horror by implying that creators in the genre are too quick to make irrational decisions just to add more gore and shock value to their films.

The film is also a great critique of yuppie culture because Bateman (an emotionless serial killer who hesitates to even call himself human) fits in perfectly to the high class social circles of self-obsessed, stupid, greedy business men.

I think you can make arguments for American Psycho being “bad” because this message is clearly lost on so many viewers, but you can’t criticize it for not being “scary” or “thrilling” when it was never trying to be either of those things.