The paralyzing ambivalence of Generation X is Brooke Berman’s subject in her latest play, “A Perfect Couple” (now at the DR2 Theatre, directed by Maria Mileaf). Ms. Berman, who has a keen ear and a sharp eye, is as unflinching as a crash-scene photographer in documenting her characters’ alienation from their chronic ambivalence: the unreturned phone calls, the relationships that stretch on for years without a glimmer of commitment, the friendships undermined by mistrust.

In this wry and often intriguing follow-up to last fall’s “Hunting and Gathering,” Ms. Berman delivers a nuanced snapshot of her generation and its discontents. But ambivalent characters make for halfhearted combatants. And when Ms. Berman tries to deploy three of them to anchor the corners of a love triangle, they keep wandering away from their assigned posts. Like its characters, “A Perfect Couple” resists structure; it’s a chain of brief episodes that often feels more like a staged screenplay than a play.

Pretty, uptight Amy (Dana Eskelson) is finally marrying Isaac (James Waterston), whom she’s dated on and off for years. The two ex-New Yorkers have taken up residence in an inherited upstate house, “with trains to the city every hour,” and Amy, who’s stopped working, is planning a Martha Stewart wedding. Next on her agenda is a baby; her biological clock is running down.

Enter Emma (Annie McNamara), the couple’s best friend, who’s up from New York visiting for the weekend. Content with her single Manhattan life — an all-consuming career in photography, supplemented by casual sex with younger men — she’s getting sick of hearing her married friends preach to her about “finding someone.”

In a series of unadorned conversations staged mostly around a farmhouse table, we observe the three friends’ relationships in action. Amy and Emma, former roommates, are bracingly frank with each other, and not especially warm. Amy and Isaac have settled into a dysfunctional, if familiar, dynamic — Amy hectors Isaac, and Isaac grudgingly takes it. Only Isaac and Emma seem to have something enviable — the easy camaraderie of two like-minded people who are naturally similar in temperament.

For all the play’s up-to-the-minute flourishes (titles are projected on a screen to demarcate its sections, and snippets of music by the band Wilco smooth over the scene changes), the play’s catalyst is surprisingly old-fashioned: a diary discovered in the attic. The diary hints at a far more complex and painful history between the three characters than the one we’ve assumed.

Yet as portrayed by the actors (directed in a clipped, stylized manner by Ms. Mileaf), these people don’t have much going on beneath the surface. Attempts to dig for secret yearnings only turn up more ambivalence.

Ms. Berman is a smart, incisive writer, and it seems plausible that she’s deliberately tapping the more relaxed, ephemeral qualities of television and film writing to make a larger point about the casual way her generation relates. This approach pays off best with the play’s fourth and final character, 22-year-old Josh (Elan Moss-Bachrach), the next-door neighbor who just graduated from Bard and is living with his parents. There are wonderful, meandering scenes in which Josh runs off at the mouth in a charmingly un-self-conscious way, sharing his not-too-complex theories about life and love with no ambivalence whatsoever.

It’s the contrast between uncomplicated, openhearted Josh and his tortured elders that gives the drama a little bite. Will Josh eventually turn out like his elders — or is he fundamentally different? That tantalizing question is among the reasons to see “A Perfect Couple,” a slight but engrossing play by an emerging playwright of considerable talent.