As a general rule, the critics are usually wrong. So, the more the critics hate it (or profess to hate it), the more likely it is to be a great movie and vice versa. I think they're just angry that they're not good enough to have any part in the making of the film, so they figure they'll ruin the industry by giving a review which is opposite their actual opinion.

For example:

They really spat all over The Butterfly Effect which turned out to be a great movie.

They gave glowing reviews to Terminator 3, which, as we all know, was terrible storywise because it didn't follow Cameron's original storyline. Mostow didn't know what the hell Terminator was supposed to be about.

I was going to see Eragon on my birthday this year, but someone who was a big fan of dragons told me it was terrible. For this reason, I decided to read the reviews. The critics loved the movie. This sealed the deal. If an expert and a critic disagree, the expert is always right. I decided not to see Eragon. I could go on all day, but you get the point.