As I understand it, Frakes had let his beard grow during the 1988 Writers Guild of America strike, which delayed production of the second season of the show (and caused it to have fewer episodes than planned).
When the strike was resolved, and the cast returned for production, Frakes still had the beard, though he fully expected that the producers would instruct him to shave it off. But, to his surprise, the producers decided that they liked the beard, and had him keep it.
I remember reading an interview with Marshall, long ago, in which he talked about that. IIRC, Marshall had been away from the show for a few weeks (I can’t remember if he’d been on a different project, or what), and, in his absence, ABC had decided that Fonzie looked too much like a criminal in the leather jacket. They’d mandated the change to the windbreaker, and Marshall had not been around to protest.
Marshall came back, saw Fonzie in the windbreaker, and said, “WTF? He’s a biker, he’s a greaser! Of course he should be in a leather jacket!” And, Fonzie got his leather jacket back.
network said Fonzie could wear the leather jacket only when he was on his bike or near it. So the writers made every scene with him follow that rule. Eventually ABC gave in and he could wear it all the time.
I thought this was more about a ‘moment’ when a show suddenly takes a jump up in perceived quality.
For me, one of those moments was when Mal Reynolds kicked the bad guy into the engine in the first aired episode of ‘Firefly’. That was the moment when I realized the show wasn’t just going to be a bunch of cliches, but was actually going to be really interesting.
So I’d say it’s the ‘kicked him into the engine’ moment. Or something like that.
For some people, it might be the moment we found out Henry Blake was killed on MASH. That turned the show in a more serious direction. For some people, that was a bump up in quality. For me, not so much.
As a long-time Happy Days fan and Fonzie fan, I think it wouldl be something like “Getting on the Bike.” When the show began, Ron Howard was the star and Fonzie was not generally shown on his bike and often not in his iconic leather jacket, lest the show seem to be glorifying gangs. When they got over that, it got good.
Rewatching the show recently, I’v noticed that in hte year when Winkler and Howard were sharing the top spot, the writers made fun of Fonzie a lot more than I recall. There’s one episode in which Fonzie, Richie, Ralph, and Potsie go off for the weekend in some wilderness resort area. The nerds get into it with some huge lumberjack – the guy must have been 7 feet tall and carrying an axe – and expect Fonzie to save them as he does every weeek, with his usual magic and off-screen violence. When Fonzie sees the brute tehy expect him to fight, even he gets scared and screams “Are you crazy!”
Just putting in my two cents regarding some other opinions:
TBBT and The Simpsons were in top form straight out of the box.
The first season of TBBT has some of it’s finest episodes. (And Amy becoming a regular was a key part of the downhill slide of the show. It has seriously messed with Sheldon’s character.)
The first few seasons of The Simpsons contain some of the all time greatest episodes of any show ever. The first season, in particular, is practically perfect. Good grief, it has “Krusty Gets Busted”!
Neither grew the beard, they had full beards at birth.
Im not sure if it’s what the OP is after but I find any series that becomes edgy or begins dealing with issues are more often than not applauded by critics.