Most movies end happily, or at least satisfyingly; that's what audiences typically crave, after all. Crowd-pleasers are a fan-favorite for a reason; who wants to see a bleak ending on the big screen, when we seemingly have enough of those in real life? The saying is "and they lived happily ever after" for a reason.

A thriller earns that 10/10 feeling when the first scene already knows what kind of pressure the movie is going to put on you. The story can be loud, quiet, violent, psychological, procedural, or strange. What matters is control. A great thriller keeps your attention without begging for it.

R-rated mystery movies have room to be uglier about the truth. They can follow obsession into places a safer movie would soften, and they can let violence, sex, grief, corruption, and psychological damage sit on the screen without cleaning the edges for comfort.