Why Don't People Like Movie Critics?

Typical moviegoers don't care for film critics. Well, a more accurate statement would be that moviegoers don't like dissenting critics. If they think a movie will be good then a reviewer who agrees will earn their praise, the opposite for a critic who takes too critical of a stance. People would like to believe that they are all experts on movies and in the end will never yield to the opinion of someone who probably knows more than them. This isn't always the case however. Sometimes film critics are wrong, even when they're right.
Roger Ebert basically revolutionized the art of film criticism, bringing to light the idea of reviewing films relative to their likely audiences and expectations. So for example, the Hangover could get 4 stars (the highest rating) not because it's as good as Casablanca, but because it's an excellent comedy. See the difference here? Whereas some more "traditional" critics review all movies as if their audience is the Academy, Ebert has chosen a more relative (and therefore relevant) style that makes sense to readers.
Not to say that there's not some disagreement even still, but in general you can take his reviews with much less a grain of salt than most others.
So taking Roger Ebert's approach seems like the obvious choice right? As it turns out...no.
Movie critics like to maintain an air of superiority because they're quite simply exclusionary and arrogant. They want you to believe that they know better than you, so some will even go so far as to trash a movie that probably doesn't deserve it. Then there are critics that buy into hype, like with Avatar, and ignore all of the important things they are supposed to reinforce. Things like plot, story, and acting. These are the type of critics that make us hate reading reviews. I strive not to fall into those categories but sometimes you can't avoid it.
In any case, give critics a chance and trust that they DO know better than you, although they may not be reviewing the film correctly as I described above. Of course, when you're not sure what to believe, check Ebert.
And if you disagree with all those sources, then become a critic yourself. Of course, make sure you know something before hand. For example, don't think you can know anything about film if you haven't seen the Godfather. Seems obvious but people who have seen a lot of modern films have an extremely incomplete definition of the art of film and are not fit to review.
So trust the reviews, but don't take them to heart. If there's an actor/director that you like and know won't let you down, then just go. Do what you like with movies because in the end art is subjective.