This is perhaps the most logical and balanced defense of critics I've ever read -- and of audiences, as well (from the daily blague):
Critics are people who are paid to pay attention. All the time, to every detail. The audience is under no such obligation. For the audience, "it's only a movie." There's no law against letting your mind wander - if you're young, you'll be having a lot of trouble preventing it from wandering. If the movie ceases momentarily to merit your attention, that's no biggie. When it's time to pay attention again, the movie will let you know.
And there are levels of attentiveness. Critics are expected to pay full attention. Ordinary viewers can pay just enough attention to keep track of the story. For regular people, for the mass audience that flocks to pay to see the film, a motion picture is not an artistic unit, with a beginning, a middle, and an end, composed of coherent parts. No. A movie is a series of moments, some of them okay, some of them really exciting, some of them funny, and so forth. When the series itself is interesting, as happens in great popular entertainment, then many people, not just critics, will come away with the sense of a powerful whole, but that experience is not really necessary to the enjoyment of a movie. This would explain the popularity of kung-fu movies, which are comprised almost exclusively of climaxes.) The enjoyment of a movie requires little more than a darkened auditorium, a moderately comfortable seat, a synchronized audience on the noise front, and working eyes and ears. That's it.