This may be the era of peak TV, but the days of “Must See TV” on NBC hold their own special place in history.

Think back to the 1990s, when shows like “Friends,” “ER,” “Seinfeld,” “Cheers,” “Frasier” and “Will & Grace” ruled the airwaves.

If you’ve read former NBC Entertainment President Warren Littlefield’s 2012 book “Top of the Rock,” you’ll know that several of these shows — now considered some of the greatest ever on television — barely made air.

Littlefield (executive producer of FX’s “Fargo” and the upcoming “The Handmaid’s Tale” for Hulu, both with MGM) was part of a Hollywood Radio and Television Society “throwback” newsmaker luncheon called “A Moment in Time: Must See TV,” held February 7 at the Beverly Wilshire Hotel.

Joining him were some of television’s best-known executives, all of whom worked in NBC programming during that period: Showtime’s David Nevins; FX’s John Landgraf; Kevin Reilly (TBS & TNT); Freeform’s Karey Burke; Robin Schwartz, head of TV at Big Beach; and Preston Beckman (The Beckman Group), in a conversation moderated by WME | IMG founding partner and television department head Rick Rosen.

As the discussion ricocheted from one telling anecdote to the next, there was an elephant in the room. Don. Don Ohlmeyer, whose last name was never mentioned. He was NBC’s West Coast president whom the panelists said fostered an environment of fear and loathing.

“He was a scary dude,” said Landgraf, now CEO of FX Networks.

“In working for Don, it united us,” Littlefield said. “We had a tough boss we all had to work for. If you really believed in something you’d better stand up and fight for it.”

Littlefield praised other Peacock Network leaders Grant Tinker and Brandon Tartikoff, who created an atmosphere of risk-taking in which programming executives could succeed.

“Grant didn’t pontificate a lot, but one of the things that he told us when we were kids running around the network is, ‘Stop thinking about the audience as a bunch of aliens out there,’” Littlefield said. Tinker instead implored them to “just put shows on that you would want to watch.”

One of those shows was “Will & Grace,” which ran from 1998-2006 and is now being rebooted with the original cast, writers and producers. The landmark comedy is considered instrumental in educating the public on LGBT issues, but Don fought it — hard.

Everyone knew it was a risk but as the pilot was being considered, Nevins recalled a meeting in Ohlmeyer’s office when Littlefield announced that they were picking it up. “Don got up out of his seat, stood over me … and said, ‘What f–ing world do you live in where you think America wants to watch [a show with gay characters]?’” Nevins remembered. “Will & Grace,” starring Eric McCormack, Debra Messing, Sean Hayes and Megan Mullally, went on to win 16 Emmy Awards.

It’s hard to believe the rocky road that “ER” started off upon. It was a dusty Michael Crichton “trunk” script in which the medical references were 20 years old, and it took John Wells’ steady hand to update the show. Reilly described the first screening of the pilot at NBC. “It was like someone farted in the room,” he said. “It was not a successful outing. We thought it was really good — but it was a patchy time for drama.”

So the prospects were not looking promising when CBS CEO Leslie Moonves, then head of Warner Bros. Television, scrambled to put together a test screening to convince the NBC team to take on the show.

Nevins said he got a call about 8 o’clock one night and drove to the Warner Bros. lot, where the “ER” screening was so well received that he was suspicious of Moonves, thinking he packed the audience with employees.

Yet another NBC screening of “civilians” living in the Valley tested very well — and the rest is television history. “ER” logged 16 seasons, scored the highest number of Emmy nominations for a drama (124, with 23 wins) and made George Clooney a massive star.

“Shows succeed because someone is willing to die for them,” Littlefield said. “We were united by it, plus it became our highest-rated drama ever. Ultimately we believed in the writers and showrunner’s vision.”

Burke, who was an associate of drama development, recalled the pitch for “Friends” by creators Marta Kauffman and David Crane.

“It was so memorable, as if they were acting out a two-hander play,” she said. “It was really brilliant, with character descriptions for each actor — 10 words that always stayed the essence.”

“I knew zero about comedy and gave sucky notes to Crane,” Landgraf recalled. “It was the best comedy ever made. Sometimes you get good by being really bad — but around great people.”

And then there was “Seinfeld,” the lowest-testing show in the history of NBC. “It was too Jewish. Too New York,” Littlefield said. “We loved it though. Preston believed in it.”

Littlefield said the development team decided to scrape together the resources by killing a Bob Hope birthday special and using the funds for four episodes of “Seinfeld.” “Bob Hope still thinks you made that special,” Beckman interjected.

“I called Jerry to tell him and he asked one question — has anything ever worked with four episodes?” Littlefield recalled. “I said I dunno, and he said, ‘We’ll do it.’ It was a beacon to the creative community and then everyone wanted to come [to NBC] because we got ‘Seinfeld.’”