The best, purest moment of The Break-Up is the opening credits, a montage of snapshots featuring couple Gary (Vince Vaughn) and Brooke (Jennifer Aniston) in sweet, unforced romantic moments, giving a history of the good times of their relationship in between their opening meet-cute (at a baseball game) and the meat of the film, which, as the title suggests, charts the relationship's acrimonious decline. Without words, Vaughn, Aniston and director Peyton Reed paint a portrait of two people who look like they really care about each other, the kind of fun, loving couple you'd like to get to know.
Unfortunately, you do get to know them, and the rest of the film reveals both Gary and Brooke as shallow, vindictive and deeply unpleasant people who treat each other so poorly during the breakup that finds them still living together in the same condo (because neither of them wants to give it up) that you feel sorry for whatever poor sap ends up shackled to either of them next. It's hard to imagine what drew these two together in the first place (and the opening scene provides no insights). Each is a basic gender stereotype: Gary works as a tour guide, likes sports, beer and violent video games, and hates doing housework; Brooke works at an art gallery, likes dinner parties, ballet and flowers, and wishes Gary would help her with the dishes. They're such stock characters that they might as well be named Man and Woman.
Promoted as an anti-romantic comedy, The Break-Up doesn't have the guts to really embrace what that would mean. Even while Gary and Brooke are doing their best to make each other miserable, the film is never willing to travel the truly dark path of something like The War of the Roses (which featured equally unpleasant protagonists, but never asked the audience to like them). Since these are big movie stars, we're meant to hold out at least a sliver of affection for them, but when the heartfelt, emotional scenes show up late in the movie, they don't have any ring of truth. Eventually you're just rooting for Gary and Brooke to get the whole ordeal over with, as much for the audience's sake as for their own.