I watched a spy movie from the 1960s recently with someone. We got 20 minutes in before she was confused about why the movie is just about a depressed drunk who lost his job in a spy agency, before my movie-watching accomplice looked up the plot of the movie on Wikipedia. Spoiler alert, there's a twist, and the movie didn't tell the viewer that.
It's interesting that modern movies have to make you think you understand something, before they pull the curtain back and reveal there's a twist. Otherwise people will get disengaged and stop watching before the twist occurs.