I think many people are going into this movie expecting it to please them, that is not what this is about.
The menu is a critique of the consumerist culture that commodifies art, burns out artists, and essentially takes the joy out of creating.
It's a critique not only on the food industry, but any service industry that reduces individuals skills and usefulness to how much money they attract.
People who are saying it wasn't a horror film, that it didn't have enough suspense or that it wasn't funny are all missing the point of the film.
We are the consumers, we are the people eating in the restaurant. Most of us take the art of film for granted, movies serve the purpose of providing us with entertainment and pleasure, and when a film fails to gratify us, we tend to go on google feedback and write a mean review.
Granted, some of us just have different tastes than others, and that is okay! just consider that cinema and art in general is so much bigger than our perception of it.
It is unfair to treat The Menu as your typical horror movie, because it isn't intended to scare or frighten you, it's mean't to provoke you and make you rethink how you approach film and other mediums of art.
i hope this helps guide you through The Menu, because it's frustrating to see so many people missing the point!