Jack Thorne’s “Sunday,” currently running at Atlantic Theater Company’s Linda Gross Theater, seems to elicit one of two responses: disappointment or robust enthusiasm. A group of Gen Z friends gather in a New York City apartment for one of what has become Sunday Book Club gatherings. This Sunday’s meeting is at Marie’s (a somewhat broken and conflicted Sadie Scott) and Jill’s (a self-assured and Juliana Canfield) place, a modest studio with a mountain of books at its center. The pair are joined by narrator Alice (Ruby Frankel), Keith (Christian Strange) and Milo (Zane Pais). Milo is now dating Jill whose relationship with Marie seems fluid.

Mr. Thorne seems to have assembled an interesting group of twenty-somethings to discuss Anne Tyler’s broken-family novel “Dinner at the Homesick Restaurant.” What is disappointing about this assemblage? This quintet is comprised of seemingly stock characters – these are important characters, just without any significant depth. It is difficult for these fine actors to develop this bunch of Gen Z “misfits” without more substantial traits and attributes. The audience members – particularly other Gen Z persons – connect to these characters “by proxy” and not because there are fully developed, real characters on stage.

Disappointing also are the dance sequences imbedded in the action of the play. There were one, perhaps two, that seem “logical” in the sense the choreography provides some exposition and some “revelation” of a character dancing around the room. Otherwise the movement, choreographed somewhat aimlessly by the arguably excellent Lee Sunday Evans, adds little to the development of the plot and is about as inspiring as Daniel Kluger’s repetitive, bass-heavy pre-curtain music that seems interminable.

That said, there should be robust enthusiasm about Jack Thorne’s attempt to portray a generation seemingly at odds with itself and searching for some identity in the present social media, dating app, “insta-gratification” culture. Although his characters need further development, their conflicts are authentic. This disconnect makes for a shaky plot development. There needs to be both strong characters and solid believable conflicts. The popularity of the piece arises from these connectable conflicts which obviously the members of the audience become surrogate characters for.

And then there is Bill (Maurice Jones), Marie’s older downstairs neighbor who, at the beginning of the play, stops by to remind her that he has work on Sunday and needs to sleep and hopes there won’t be too much noise coming from the book club. Bill seems to have some feelings for Marie; however, she handily dismisses him. But Bill returns at the end of the play to share with Marie all the things he likes about her and his hope to get to know her better. This scene is the most convincing scene in “Sunday.” Mr. Jones and Ms. Scott are magical here but to say more about what ultimately transpires during the visit would be unfair to future audiences.

Mr. Thorne rightly recognizes the importance of Gen Z’s concerns for “owning” a personal morality. Keith challenges his friends to identify their personal morality by presenting a hypothetical situation about what each would do as a thirteen-year-old if confronted with the decision whether or not to dance with someone who “tells you that you’re attractive [yet] happens to have Down’s Syndrome.” Thorne also explores this generation’s confusion between having “self-pity” and “being reflective.” The issues of alcohol and drugs (cocaine) are also addressed with honesty.

Lee Sunday Evans directs this conflicted piece with great sensitivity. She knows how to bring the best from her cast. However, even her direction, the scenic design by Brett J. Banakis, the costume design by Ntokozo Fuzunina Kunene, and the lighting design by Masha Tsimring cannot substitute for the lack of rich characterization which unfortunately tips the disappointment – robust enthusiasm scale more toward disappointment.