Andrew (Seth Rogen) is a science genius who has invented a new multi-purpose cleaning product that is both better and safer than its existing competitors. Having invested all of his money into it, he's suddenly finding it hard to get any major stores interested in buying it. One of his sales pitches happens to be near where his mother Joyce (Barbra Streisand) lives, so he decides to stop by for few days. One night while staying up late, Joyce reveals to her son that there was another love-of-her-life before her now-dead husband, so Andrew invites her along on his cross-country sales pitch drive, the final stop being in San Francisco, where he intends to reintroduce his mother to her old flame.
But this being a mother-son road-trip, arguments ensue. Joyce does what every loving mother does and gets too involved in her son's life, still very much treating him like a child, while Andrew does what any child would do, and gets overly embarrassed by his mother's doting affections. There are mild annoyances, petty squabbles and full on tantrums from them both, and the entire back-and-forth between the two of them is quite irritating. It's mild, inoffensive, but completely lacking in any kind of originality or depth, and both Rogen and Streisand's characters are all kinds of annoying throughout.
About two thirds of the way through, Joyce partakes in a steak-eating competition (as you do) and from then on the movie becomes significantly more bearable. Director Anne Fletcher (Step Up, 27 Dresses, The Proposal) knows how to wring the most out of a clichéd situation, and does her best here to extract some mild chuckles along the way. Plus, as irritating as Andrew and Joyce both are, audience members will undoubtedly find them both all too relatable, with their over-the-top relationship coming from a very honest place.
The Guilt Trip is basically two actors collecting their paycheques in the most vanilla of comedies imaginable. Not irredeemable, but not recommendable either. A shrug of a movie, with everyone involved basically saying "Meh."