Here's the complete list of reasons not to see it:
- [this space left deliberately blank]
Special effects in Hollywood seem to cause a peculiar form of amnesia in movie makers whereby they forget to add a story to the movie. Pixar's movies, which have been completely computer animated and are in some sense the very definition of "modern special effects", have been the shining counterexamples, and this movie is no different. If you liked the Toy Stories or A Bug's Life, you'll like this movie. Period.
Much like those movies, Monster's Inc. is the very definition of a family movie, as opposed to a children's movie with jokes for the adults thrown in as a concession to the people REALLY paying for the ticket. The plot is funny, well paced, well assembled, and successfully carries the movie. Bring your kids, and your imagination. (You won't need your "inner child"... your "inner adult" should find the movie sufficiently enjoyable.)
I don't believe in recounting the plot in a review, so I'll let it stand with this: A bigger culture clash one can hardly imagine.
For a vastly more whiney view of the movie, written by a review who was annoyed because the movie wasn't the movie they wouldn't have written, see this Salon article. (No, really, the whole review is a description of the movie the reviewer would have written, or perhaps more accurately, expected to see. The reviewer doesn't actually review the movie they saw.)
Oh, and if you care, the tech's cool. Watch the hair on the main character. Wow. But the story's the thing.