Jaroslav Pelikan declared, “Tradition is the living faith of the dead, traditionalism is the dead faith of the living.” But it can be hard to tell which one you’re actually doing.

Bad Jews,” at the Studio Theatre through December 28, takes place over a few hours in one tiny (but pricey) New York apartment. Cousins Daphna, Jonah, and Liam are reunited on the night after their grandfather’s funeral. (So big, even Abe Foxman was there!) Liam has also brought an outsider: the blonde, beatifically-smiling Melody (Maggie Erwin), a 1950s Coca-Cola ad of a person, whose sunny shiksa demeanor couldn’t be more of a contrast to the rest of his family.

Most of these people are awful in their different ways. Daphna (Irene Sofia Lucio) has burrowed into her Judaism like a tick, swelling with the righteous blood of the Jewish dead. At no point does her faith make her act better. We never see her pray; we never see her give up anything she really wants in order to follow God. In fact, God isn’t mentioned. She’s catty and racist, and she’s appointed herself to defend the family’s religious and ethnic heritage against the lukewarm assimilationism of Jonah and Liam.

This allows Daphna to get off some great lines. She pegs Liam as a type we’ve all encountered, who loves any tradition as long as it’s somebody else’s. She calls him “proud of how disdainful he is” toward his heritage.

“Oh, if you found yourself in the middle of a rain dance, you’d be perfectly respectful,” she rants, prancing around the apartment in her imitation of a Native American ceremony. “But if you find yourself in the middle of a hora—I’ve seen you in the middle of a hora!—you want to die.” Like many people in our culture of religion-switchers (I’m an adult convert so I have little ground to stand on here), Liam never bothered to seek an adult version of the childhood faith he rejected.

Daphna is crazy-eyed and gooey-faced. Liam (Alex Mandell) at first seems more reasonable, but she pushes his buttons, and they end up in a nuclear war of judgment which has him howling into her face and saying some truly filthy things. (There’s a line about a shofar which had the audience laughing in “Did that just happen?” horror.)

These characters aren’t quite caricatures. Melody does live up to Daphna’s instant assessment that she “looks like she was conceived and water-birthed in a Talbot’s“—her belief system is a cross between Lennon’s “Imagine” and a second-grade Thanksgiving pageant. But she’s also a gentle person, who clearly makes Liam better than he would be without her. She’s able to get off some sharp lines of her own. I loved the little grunt of frustration with which she punctuated her complaint that the family talks “in this—hnnnn!!—horrible way.”

Jonah (a truly fantastic Joe Paulik, able to get laughs with just a tilt of his head) at first seems like a mere audience-identification character, or even an irrelevance. He lurks around the edges and oozes away from the fights. But in the play’s final moment he reveals his own way of grappling with the family’s Jewish legacy, a moment which sent ripples of shock and confusion through the audience. Jonah’s gesture brings the play together and makes its central conflict obvious.

What Daphna and Liam are ostensibly fighting over is the disposition of an item of jewelry. This is a chai necklace, which belonged to their grandfather and which he hid in his mouth throughout his years in a concentration camp. The Hebrew letters mean “life,” and at the center of “Bad Jews” is the question of what it means to give Judaism a future. Liam is going to have kids (there’s a weird and unnecessary bit in which the play itself seems to agree that Daphna has never experienced romantic love), but they won’t be Jewish kids in any life-shaping sense. Daphna points out that if everyone lives like Liam, in a few generations Jews will disappear. And yet her own Jewishness seems museum-like, a Civil War reenactment, a kid dressing up in her dead grandfather’s clothes.

I didn’t read much about the Holocaust when I was a kid. My understanding of what it meant to be Jewish was shaped more by Purim at the JCC, Isaac Bashevis Singer’s Hanukkah stories, and tales of the New York immigrant world than by pogroms and persecution. On one level I think that’s better0–better to be formed by stories of Jewish life, not Jewish death. On another level it’s false to Jewish (and Christian) history. It’s an incomplete picture. And, as Daphna would point out, it makes it easier for me to be Christian; I had less guilt in conversion (less guilt, not no guilt) than I would have had if I’d been raised with the Holocaust closer to the center of my identity.

“Bad Jews” is a conversation-starter: Many families have had these highly symbolic fights over how to distribute the possessions of the dead. And even the goyim among us have conflicted relationships to the culture and traditions of our childhood. One man’s hora is another man’s Jell-O salad. Joshua Harmon’s play is ferocious and fast-paced; and very funny, if you don’t mind being lacerated while you laugh.

Eve Tushnet is a TAC contributing editor, blogs at Patheos.com, and is the author of the recently-released book Gay and Catholic: Accepting My Sexuality, Finding Community, Living My Faith.