After decades of vanity projects and long stretches away from the silver screen, it's easy to forget that, early in her acting career, beloved singer Barbra Streisand seemed able to conjure the spirit of the classic screwball-comedy heroines of the 1930s. She approached comedy like she would a song -- she understood it was all about the timing -- and she could bring energy and a snap to her line deliveries that made her, and them, stand out. There are moments where that skill still comes through in the 2012 comedy The Guilt Trip. She plays Joyce Brewster, a sixtysomething widow who has given up on men and seems to spend most of her free time phoning her son Andrew (Seth Rogen), a chemist who has created an all-natural cleaning solution that he's bet his career on and is trying to sell to retailers (a wager that he's losing thus far). As the movie opens, Andrew returns home to spend some time with his mom before going on a cross-country road trip to pitch his product in various cities, ending with a trip to Las Vegas where he'll shoot a Home Shopping Network demo. During their time together, Joyce, who has abandoned dating, tells Andrew about Andrew Margolis, the first love of her life -- the man she named her son after. She never made an effort to find her old flame again after she got married, but with an Internet search and a phone call, Andrew believes he's located the man in San Francisco. He asks his mother to join him on the road trip, planning to surprise her with a final stop at the home of her lost love. Jewish mothers are one of the more enduring archetypes in comedy, and as written by Dan Fogelman, Joyce is, in the beginning, a pure, undiluted dose of nagging, guilt-inducing maternity. However, with Streisand's skill, Anne Fletcher's laid-back direction, and Seth Rogen's expert support, the setup is charming in its familiarity. The movie hits a comic high note with a lengthy monologue from Joyce about her first love; it's a well-written, expertly acted speech that ends with a killer punch line that ranks among the all-time-great Jewish-mother jokes and reveals the emotional stakes for the rest of the film. Oddly, just when everything seems to be in place for a light, enjoyable comedy, the energy goes out of the movie altogether for about a half hour. Their bickering in the car doesn't have any bite or wit, Andrew's failed pitches aren't particularly memorable, and it's quite possible that the film's intended older audience might be napping. Just when you've given up hope that anything interesting could happen, mom and son finally have their first real fight and say horrible things to each other, prompting Joyce to storm off to a nearby bar. Although they make up quickly -- in no small part because Andrew gets into a fistfight with a redneck who's trying to get Joyce drunk -- that scene snaps some life back into the proceedings. Although it's a movie with significant star power, The Guilt Trip plays more like a short cable series with a good pilot, a couple of crappy episodes, and then three good ones. It doesn't have the narrative drive or enough character depth to stick with you, but Rogen's expert timing makes sure it never entirely derails. He gives a rather selfless performance here, allowing Streisand to be as wacky or as naggy as she cares to be without ever letting us feel like she's going over the top. He's a rare comic talent who has the energy of a leading man but the instincts of a first-rate character actor, always willing to serve the scene rather than his own desire to score a laugh at the expense of the situation or the other performers. As good as Streisand is, you can picture somebody else in her part, but the same can't be said of Rogen. Savvy marketing put The Guilt Trip in theaters over the holiday season; it's exactly the kind of film that appeals to older moviegoers, and while it doesn't break new ground, it will play well for all those who appreciate Streisand or want to be reassured that their adult children still love them.