We know what you're thinking. "Barton Fink," right? Well, whereas that's one of our favorite Coen brothers movies (and if we were to rank their films, it would end up near the top) we don't think any movie that won the Palme d'Or could be considered "underrated." Mostly unwatched, sure. But underrated? Naw.
How about "The Hudsucker Proxy?" Well, while we do enjoy that picture, and feel that it's underappreciated, we wouldn't call it underrated, either. With a 60% Rotten Tomatoes critical score, we think it's perfectly rated.