In Anne Fletcher’s (27 Dresses, The Proposal) latest directorial endeavor, The Guilt Trip, Seth Rogen and Barbra Streisand team up to play mother and son Brewster – Andy and Joyce. The plot has Andy, an organic chemist entrepreneur who has set up a cross-country pitch meeting tour for his Sci-O-Clean product, invite his perpetually nagging mother along for the ride so that he can reunite her with the self-proclaimed love of her life – and his namesake.

The opening scenes of The Guilt Trip somewhat tritely set up the title trip across the country. Andy is broke, having left his job with the EPA and put all of his savings into his organic cleaning product. His mother, Joyce, is the prototypical Jewish Jersey mother – pestering him about his love life, his water intake, and discount shopping while bragging about his academic and professional prowess to her best gossiping lady friends over dinner.

It’s Joyce’s meddling nature that leads Andy to invite her on his road trip. In a show of great concern and sense of blame for her son’s “relationship dysfunction,” Joyce recounts her life’s great unrequited love who happened to not be her husband, but Andy’s dad, a man by the name of Andrew Margolis. In what appears to be motivated by both a wish to mend his mother’s heart and a deep desire to get her attentions off of him, Andy locates Andrew Margolis in San Francisco and resolves to take his mother to him with her being none the wiser.

Streisand was last seen on the silver screen in Meet the Fockers opposite Dustin Hoffman, playing Ben Stiller’s mother. There’s a lot less nuance in her maternal character in The Guilt Trip. Predictably, she struggles with technology, makes racially insensitive remarks, and thrives off the maxim, “I was just trying to help.” Her biggest quirk (unless you count her successfully shoveling down 4 lbs. of steak in two hours) is her ritualistic bedtime M&M munching that gives Streisand a chance to hilariously attempt to stifle the sound of her crunching as an exasperated Andy tries to sleep.

Like the M&M scene, it was the subtler scenes that worked best. Another was when they stop at a gas station and Joyce comes out of the mini mart only to hop into the wrong car. Most of the dialogue between Streisand and Rogen grated on the eardrums – Rogen’s grizzly growl, pierced with Streisand’s screeching soprano. Perhaps the difference in their volume and disposition was meant to be played for laughs, but it only worked when the mother-son duo engaged in the only semi-non-passive aggressive fight of the film when Babs perfectly delivers the final line – “Drink your f—ing water before you die from dehydration” – before going down to the Motor Lodge bar and getting more inebriated than her son. All in all, Streisand showed her ability to make do with a mediocre script where Rogen seemed to be phoning it in – strange considering Rogen chased Streisand for years to make the movie.

As The Guilt Trip winds down, Joyce and Andy develop a more amiable rapport – until Joyce discovers that Andy’s motive in bringing her along had more to do with getting her back with her old flame than with his desire to hang out with his mother. Her disappointment soon dissipates as she witnesses him heeding some of her sage advice, and she agrees to go with him to San Francisco. That long uncovered love story is tied up nicely in a way that’s admittedly less predictable than the rest of the film. And, the love story of mother and son sweetly culminates as they part ways in an airport terminal.

When you look at the premise of The Guilt Trip, it shines with possibilities from both a storytelling and comedic perspective. But this film fell flat in too many of its 95 minutes for it to be considered a new family classic. While it wasn’t without laughs (the book on tape of Joyce’s choice was Middlesex), they were often forced as if injected haphazardly rather than out of the natural narration of the story. It could have been better, but it wasn’t. And maybe when Rogen was chasing after Streisand, he should have been searching for the guy who’d shown up in 50/50 and Knocked Up.