Sad, funny, and acutely self-conscious, Noah Baumbach's new movie is a mordant character study, unafraid to project a downbeat worldview or feature an impossible protagonist. But unlike Nicole Kidman's pain-in-the-ass writer in Baumbach's Margot at the Wedding, loser Roger Greenberg (Ben Stiller) is also painfully poignant. Baumbach's sixth feature is his first to be set in Los Angeles, and the director wastes no time commenting on the milieu. Introduced navigating Sunset Boulevard, Florence Marr (Greta Gerwig) is the personal assistant to a Hollywood Hills hotshot who is packing up his family for a vacation in Vietnam. The ever-obliging Florence is supposed to do whatever she can for her boss' brother, Roger, who, newly released from a mental hospital back East, will be house-sitting and looking after the family dog. Making no bid for audience sympathy, Stiller plays Greenberg with the haunted look of a man not more than a single missed cue away from total rage. A failed rock musician turned carpenter, he's a cranky, opinionated, self-pitying know-it-all who explains that his current project is "doing nothing," which includes writing unsent letters of complaint to Starbucks and Michael Bloomberg. Not much happens in Greenberg. It's a movie of throwaway one-liners and evocatively nondescript locations. The style is observational, the drama understated—and when the time comes, it knocks you out with the subtlest of bada-booms.