In ‘Uncut Gems,’ Adam Sandler is supremely annoying – and that’s why he’s so great

On paper, the character of Howard Ratner, a New York City jeweler of wayward moral and decision-making instincts, does not seem to be the kind of guy with whom most people would want to spend time.

Even on a movie screen – where your exposure to him is limited to a couple of hours or so, and the obnoxiousness of the character is tempered by the undeniable charisma of actor Adam Sandler – “Uncut Gems” is a pressure cooker of a movie.

For most of its duration, we’re invited to spend time with a wheeler dealer and compulsive gambler who seems to perpetually be having at least two simultaneous conversations: one kvetching, one horse-trading and both conducted with the speed of someone under a deadline and at the volume level normally reserved for sporting events.

It is, ironically, the sporting world that gets things going – and then wrecks them – in the new film directed by siblings Josh and Benny Safdie (“Good Time”) working from a screenplay, co-written by their longtime collaborator Ronald Bronstein, that’s so anxiety-inducing it ought to come with a surgeon general’s warning.

As the film opens, Howard is dodging thugs who are trying to collect a debt he owes his loan shark brother-in-law (Eric Bogosian). Howard’s repayment plan isn’t simple – nothing in this careening, pinball game of a plot is – but it all revolves around a paperweight-size chunk of rock Howard has just received in the mail from Africa containing several raw black opals: the uncut gems of the title.

(The film opens in 2010 in an Ethiopian mine where the Safdies’ camera seems to dive inside the stone, on a molecular level, segueing to the inside of Howard’s guts as he undergoes a colonoscopy, two years later, back in the States. To what end? It hardly matters, except to signal the wild detours that will be taken by the film’s story line. Volatility is a Safdie brothers hallmark.)

Howard plans to sell the rock at auction, where he expects it to fetch $300,000. But before he can do that, he is asked to lend it to basketball player Kevin Garnett, playing himself, who admires it as a good-luck charm and who leaves his Celtics championship ring with Howard as collateral.

Maybe the rock is magical – or maybe it is cursed. Who knows? One person it doesn’t bring luck to is Howard. Think back to that opening scene in the opal mine: There’s a shot of a grievously injured miner. Long story short: Howard pawns the ring for cash, which he turns around and uses to place a bet on a Celtics game, which – well, just watch the darn thing unfold.

To be sure, “Uncut Gems” is a stressful endeavor. The story, which also involves an angry ex-wife (Idina Menzel) and a mistress (Julia Fox) who ticks Howard off when he catches her messing around with the singer the Weeknd at a nightclub, is full of mishaps, misinterpretations and loud – very loud – arguments.

It’s entertaining, but not in any traditional, or even nontraditional, sense of the word: “Uncut Gems” is more like watching a bunch of bickering people you’re suddenly relieved to discover you don’t know personally.

The film’s climax takes place inside Howard’s claustrophobic shop in the Diamond District, which has glass security doors that have to be buzzed open. On the inside of the locked glass is Howard, and on the outside are people who want to kill him. (In this movie, that could be almost anyone.)

The score by Daniel Lopatin, a musician who works under the name Oneohtrix Point Never, amplifies the irritation to the point of angina with intrusive synthesizer music that sounds like it was lifted, at times, from a video game and at other times from an X-rated video circa 1985.

But Sandler is so good, so committed and so watchable that, despite everything – Howard’s irrationality, a rogue’s gallery of unpleasant characters, the foreboding of a bad, bad end – you can’t take your eyes off the screen, which Sandler seldom vacates.

Sandler himself has – not inaccurately – described Howard as selfish, but the character also is a cockeyed optimist, a dreamer, the quintessential American striver. He’s not a hero exactly, except perhaps a tragic one: a man whose gifts and whose flaws are, like 5,000 carats’ worth of precious stones stuck in the middle of a worthless rock, inseparable, complicated and beautiful.