Last week’s accusations about a toxic work environment at “The Tonight Show Starring Jimmy Fallon” ignited a thunderous round of celebrity gossip — disappointment and distress for his fans, sustenance for his critics and fodder for all students of entertainment-world scandal. The Fallon story, which appeared in Rolling Stone, echoed the news from just a few years ago about “The Ellen DeGeneres Show.” Staff members at both shows spoke of unreasonable demands and unpredictable anger.

Outrageous offscreen provocations are a staple of show business; the diva-like behavior of rock gods, movie stars and opera sopranos fills the pages of every edition of Tales From the Front Line of Fame. But these tales have special resonance when they involve talk show hosts because their affable, easygoing charm is elemental to their appeal. They’re friendly and they’re easy to talk to — that’s the whole point.

Having interviewed a great many of these hosts over the years and having witnessed both their deep stores of talent — as comedians, as impressionists, as musicians — and their almost equal measures of fragility, insecurity and vulnerability, I can say that the combination of charm and chaos is not a contradiction. It’s not even a rarity. It is a direct effect of the way these shows are structured. On air, the fun is infectious. Off air, the ambience can be like the hold of a Roman galley: Everybody’s rowing, but the flogging can get unpleasant.

Unlike stars in almost any other genre of entertainment, TV talk show hosts are often carrying the entire enterprise: the hiring of every chief player, from the bandleader to the announcer; the selection of the jokes; the decisions about the sketches; the publicity; the interactions with the guests — all headed by the name on the marquee. The pressure to be the singular front of the whole operation is only increased because the performers are playing themselves, the people they were in high school, the people who have to call a plumber to the house when the sink leaks. Their success depends on their ability to convince an audience that it genuinely knows them.

It doesn’t, of course. In TV’s earliest days, Sid Caesar was one of the medium’s most beloved stars, but his off-camera rages were legendary. He once held Mel Brooks, his writer at the time, out a hotel room window because Mr. Brooks had complained about Mr. Caesar’s stinky cigar smoke.

David Letterman was intense and rarely satisfied (despite the adulation he got from fans and critics alike) and prone to outbursts of rage that could include throwing things around his office.

Conan O’Brien, a genial soul, somehow got a reputation for intimidating his staff, to the point that new members apparently got warned not to make eye contact with him. He was so flabbergasted when he found out that he turned it into a sketch in which he was played by Jim Carrey as a bullying egomaniac who punishes an intern by throwing coffee in his face.

Even at shows where employee morale is good (they do exist), the late-night format is a notorious pressure cooker, inspiring a lot of offscreen talent to migrate to relatively saner pursuits, like writing movies and pitching sitcoms.

At Mr. Fallon’s “Tonight” show, an undercurrent of contention roiled behind the scenes for years, as writers, producers and showrunners arrived and departed like migrating birds. It was perhaps inevitable that it would eventually boil over for all to see. But two other occasions when a host’s offscreen life spilled out into public view demonstrate that speaking about uncomfortable topics with honesty and directness can increase the bond between audience and star.

In 2009, when news broke that Mr. Letterman had spoken to a grand jury about being blackmailed, he had to address it — along with the context that he had had sexual relationships with female members of his staff. He did so without flinching. Striking a much more emotional note, the other Jimmy — Kimmel — stood up in 2017 and told his viewers about a terrifying health scare that his baby son had faced. In both cases the hosts cracked open their well-curated on-air personas. It made both men more human and relatable.

How these hosts react to the relentlessness of the spotlight often comes down to how well they can deal with real life. With enough money in your pocket and applause in your ears, it is extremely easy to lose touch. Mr. Fallon, whose show, like all the others, is on hiatus because of the writers’ strike, quickly held a Zoom meeting to apologize to his staff. That may help with the unhappiness backstage. It’s not yet clear how it will play out for Mr. Fallon with his fans.

With vastly more scrutiny, thanks especially to social media, the job is far different from when Johnny Carson was in charge. He could maintain a genial onscreen persona while being aloof in his private life. Viewers may no longer expect their hosts to be infallible, but they do expect them to be authentic — or at least good at faking it.

Mr. Fallon has enjoyed great benefits from being likable and has suffered harsh and sometimes unfair criticism from people who find him phony. Some part of his winning charm was that it seemed he still couldn’t believe he’d landed the gig.

As he’s told me, he recognizes that his career was once in a sharp decline and becoming a late-night host revived it. And like the others, he says he loves the work. The best advice for him to follow probably comes from Mr. Kimmel, who once summed up to me his experience as a TV host: “Enjoy it while you can.”

Bill Carter, who covered TV for The Times for more than 25 years, is the author of two books on late-night television, “The Late Shift” and “The War for Late Night.”

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