Tolstoy might’ve got it wrong: Some familiesare unhappy in ways that seem quite familiar. Take the eponymous clan of Russian-extracted Jews who populate The Moscows of Nantucket, Sam Forman’s breezy—as in light and fast, and also as in set-entirely-in-front-of a beach house—comedy, now in its world-premiere run at Theater J: Richard and Ellen are living out their retirement in comfort, even if Ellen has to remind her husband to quit checking stocks on his BlackBerry and feel her up now and then. Their elder son Michael is a successful TV showrunner who does saki bombs with J.J. Abrams and borrows Katherine Heigl’s vacation home for his romantic getaways, though it’d impress his parents more if he’d find himself a nice Jewish girl instead of, well, Heather Haney—though she, and her character, a TV starlet who grew up in a Georgia trailer park, are both quite nice.

The other Moscow boy, Benjamin, is a would-be David Foster Wallace—er, would-be Jonathan Safran Foer, let’s say—whose fiction used to run in The Atlantic but who is now a permanently bathrobed drunk who lives with his folks. He resents Michael’s success, or at least the fact that his brother never thought to mention to him that he and Dave Eggers are buds.

So Tolstoy was right about unhappy families; it’s just that the Moscows aren’t truly unhappy. The way Bob Rogerson and Susan Rome, as Richard and Ellen, shoot each other an approval-soliciting glance when one of them cracks a joke shows us they’re still in love. There’s isn’t much real darkness here, nor much surprise, but the thing succeeds anyway, borne aloft by the chemistry of a uniformly strong cast. You kind of wish the Moscows would invite you out to the island for a week of recreational kvetching, too. As Benjamin, James Flangan is the soul of the enterprise: His queasy empathy keeps the whole thing from feeling too sitcom-frivolous. He’s eyeballing the abyss at present—and even his dad seems to be giving him a wide berth lest the stench of failure prove communicable—but Benjamin’s had the good fortune to hit bottom in a house owned by the people who love him most in the world. That’s a lucky thing, because family is priceless. Also, it’s probably a pretty sweet house.