This flaccid rewrite of Four Weddings and a Funeral (same screenwriter - Richard Curtis [he has five feature films, including the wonderful The Tall Guy, to his credit, and already he's repeating himself] - for both pictures) might not have been so bad were Hugh Grant's act not wearing so very thin. But his befuddled good-guy, so hapless yet charming in the earlier movie, no longer pleases. The movie gods have smiled mightily on Grant, it seems: they keep writing the same character for him to play. You have to wonder if the guy has any range at all.
Then there's the problem of Julia Roberts. She's so unactorish in her role in the beginning that when the script calls for her to turn into a spoiled brat you don't believe it for a minute. Roberts doesn't have the skills to make the role work as written.
As a matter of fact, there's very little in the movie that does work. There's no chemistry between Grant and Roberts whatsoever. Grant's roommate is such an ass that you know he's only tolerated because he's a plot device. Grant's character is so liberated that he's actually playing the female role, as it were, in the movie, at least in terms of standard movie stereotypes. Roberts breaks his heart not once, not twice, but three times, yet still he comes groveling back (in a scene that's so flat and flimsy it's see-through). It's supposed to be "because he loves her," but by the end of the movie you're certain it's because he has such low self-esteem.