It’s always a shame when superb performances get mired down in melodrama — like serving a tantalizing appetizer with an indigestible meal.

Altruistic holistic healer Beatriz (Salma Hayek), a middle-aged Mexican-born divorcee, is having a rough time. Her Los Angeles neighbor objects to the incessant bleating of her pet goat, and her old Volkswagen barely starts when she turns the ignition.

Nevertheless, Beatriz wears a perpetually beatific expression as she heads off down the coastline from the cancer clinic where she works to an exclusive Newport Beach enclave to give a massage to Cathy (Connie Britton), a wealthy client whose teenage daughter Beatriz helped recover from chemotherapy.

Not surprisingly, Beatriz’ car breaks down in the driveway. So Cathy convinces her husband, Grant (David Warshofsky), a contractor, to graciously include Beatriz as a “friend-of-the-family” guest at a small dinner party they’re hosting for Grant’s boss, Douglas Strutt (John Lithgow), a billionaire real estate tycoon who owns hotels and golf courses around the world.

Pompous Strutt arrives with his third, much-younger wife, Jeana (Amy Landecker), along with Grant’s junior colleague Alex (Jay Duplass) and his social-climbing wife, Shannon (Chloe Sevigny).

After first mistaking sanctimonious Beatriz for a maid, Strutt further infuriates her by showing off iPhone photos of his latest ‘trophy’ hunt in Africa — in boastful poses reminiscent of Eric and Donald Trump Jr.’s gloating over their “big game” killings.

Heavyhandedly written by Mike White and directed by Miguel Arteta — previous collaborators on “Chuck & Buck” and “The Good Girl” — it’s a predictable parable about the entitled “haves” and long-suffering “have-nots,” forced by circumstance into a social interaction in which there’s a presumed intimacy with an employee.

While waiting for the inevitable confrontation between passive-aggressive Beatriz, burning with righteous indignation and imbibing far too much wine, and vulgar, capitalistic Strutt, the concept collapses. White and Areta clearly cop out by inserting incoherent magical realism that never rings true.

On the Granger Movie Gauge of 1 to 10, “Beatriz at Dinner” is a deeply flawed 5, and ultimately frustrating.