Formula for "Four Christmases":

Take "Meet the Parents" and add a relatively pain-free Christmas angle. Take one part from each of two famous and tragic Hollywood breakups. (Reese Witherspoon of once Reese and Ryan Phillipe and Vince Vaughn of Jennifer Aniston’s first post-Pitt rebound relationship.)

Obviously the result will involve some indirect chemistry. You can practically feel Reese Witherspoon smelling the Brad Pitt leftovers lingering on Vaughn. There will also naturally be some humor, especially because the script is so talky and so reliant on zany families that discuss sex too much.

The most awkward thing about "Four Christmases" is that the part is completely wrong for Vince Vaughn. It’s effeminate, and rambly. He neurotically ruminates details instead of asking questions, and frequently tells Witherspoon that she’s "amazing, so amazing!" If it would have made any sense in context that the part were played by a younger hearthrob, Michael Cera would have been perfect.

Final verdict: go to this movie only as a means of compromising with family.