The short and simple answer is, "the entire first half." The longer, more complicated answer is....well, it's just not a tangible experience for much of its running time. And that may seem quite hypocritical to say, given the fact that there was no less tangible film in 2008 than Synecdoche, New York, and I loved that film in ways I've yet to fully describe. And, in reality, the underlying themes of both films are similar: the wisdom of life comes from grasping life's subjectivity, but most of us are simply unable to gain such wisdom. The difference between the two films are their methods; Charlie Kaufman uses oddity and disorientation to make the audience feel the weight of life's mysterious and confounding nature, while David Fincher and Eric Roth attempt to tell a high-concept story in classical form, with clear-as-day symbolism, cliched quirkiness, and even traditional story book-ends (which haven't been effective in any film in recent memory), and only treat it as if it were mysterious. The outside-the-box vision of the former defines it's brilliance; the calculating construction of the latter solidifies its shortcomings.
To be honest, I don't want to hate on The Curious Case of Benjamin Button. Once the film reaches the halfway point--when, for whatever reason, Fincher & Co. decide to drop the Oscar-prancing sanctimonious act and just let the images speak and the actors let loose--I grew to enjoy and admire the film much, much more. I can say with total honesty that this is a good film. There are even elements of greatness to it. The film is extremely well-made; empirically, all the ingredients of masterpiece filmmaking are in place. But Benjamin Button is not a masterpiece film.
So we return to attack the central question once more: what's wrong with Ben Button? Well, let's focus on the source material. It is well-known that the film is based on a short story by F. Scott Fitzgerald, one of the greatest American writers ever...if not the unmatched greatest. I have read lots of Fitzgerald, but I have not read Ben Button. But the film version has piqued my interest in the story, because I feel pretty clearly that the material works better on the page than it does on the screen. The powerful grasp of Fitzgerald's language and the heart-breaking beauty of his symbolism would likely turn a story like this into something truly extraordinary. The problem with Ben Button: The Movie is that Fitzgerald, unfortunately, is dead, and therefore unavailable to adapt his own story into a screenplay. Instead, Eric Roth, an effective screenwriter in the past, has applied his own long-winded, cold, distant, relentlessly square-jawed style to a story that has no purpose being any of those adjectives. As a result, the film has been mounted to look and sound like an epic, but feels like a project that went 10 degrees askew. Certain scenes fly high, hitting a powerful note of cinematic power. But more often, the wannabe-classic moments feel like they are stuck in neutral, wanting desperately to reach a transcendent take-off velocity but borne back ceaselessly (thanks, FSF) to the ground by their very literal cinematic interpretation.
The acting is solid across the board, though the only performance that stands out among the group is Taraji P. Henson's, as Benjamin's adoptive mother, Queenie. She brings a spirit and a soul to the character that is notably absent from the rest of the film, and she will likely garner an Oscar nomination for her trouble. Brad Pitt has always been a fine actor, and he is good here--better, in fact, than one might expect given the fact that he is hindered by overly precious CGI and makeup effects for 3/4 of his screen time. Cate Blanchett is luminescent and brilliant no matter what the material, but in this film, playing this character, she is a slain victim of an incomprehensible character with very conflicting (and therefore distracting and ineffective) motivations. I think the material confused her into delivering merely solid work. But then again, I question some of Benjamin's motivations in the film as well, which in turn gets in the way of Pitt's work.
So in the end, what's truly wrong with Ben Button? Well, enough to make it one of the year's most notable disappointments, as well as one of its most intriguing misfires. Film is a very tenuous medium, one that oftentimes relies on the magic convergence of all the right pieces. The best films have a spark that cannot be easily identified. The Curious Case of Benjamin Button fails to soar because the ingredients simply don't come together. Working with a technically pristine script from Roth, director David Fincher makes every effort to make every shot as magical as possible...and in his effort, he forgot that alchemy cannot be manufactured.
Of course, Oscar nominations can be manufactured, and that is likely exactly what these guys have pulled off.