If Sideways seems like Alexander Payne’s most conventional film, that’s partly because it saves its most confrontational scenes for the final act. Still, the latest from the director of Citizen Ruth and About Schmidt does corkscrew its way to Payne’s happiest ending yet, and its fundamental weakness is one that’s commonplace in Hollywood odd-couple flicks: the essential incompatibility of the central duo. It’s difficult to accept that the tale’s 40-something college roommates—crabby, despondent Miles (Paul Giamatti) and narcissistic Jack (Thomas Haden Church)—would even stay in touch, let alone that Jack would ask Miles to be his best man or consent to a weeklong bachelor-party road trip that indulges Miles’ interest in wine. A TV actor whose career highlights are behind him, Jack is about to marry a woman who’s substantially younger and wealthier than he is, but the clod intends to risk the relationship with a final fling. Schoolteacher and would-be novelist Miles, meanwhile, broods over his ex-wife, whose remarriage is a piece of unwelcome information he’s about to receive. Visiting Santa Barbara–area wineries and a wine-oriented restaurant Miles has frequented in the past, the men pair up with two oenophile gals: Miles with pretty, sensitive Maya (Virginia Madsen) and Jack with the wilder Stephanie (Sandra Oh, Payne’s wife). Miles and Maya merely chat and share a single kiss, but Jack gets the uninhibited sex he craves—at least until Miles lets the news of Jack’s imminent wedding slip, after which Stephanie turns out not to be so easy. In one of his character-establishing scenes, Miles extols the refinement of pinot, his favorite grape, as “thin-skinned, temperamental” and “in need of constant care and attention.” Payne and longtime co-writer Jim Taylor (who worked from Rex Pickett’s novel), intended this to be a pivotal speech. Yet Giamatti’s performance never makes the leap from another revealing moment—when he finances the trip by stealing cash from his dotty mother—to this one displaying the tender, complex character he’s supposed to have become. By the time Miles’ luck changes dramatically for the better, the script has utterly outpaced plausibility.