The first season of a show is almost always rough, because the writers are still getting the hang of the characters and stories. The ingredients for a great show are there, but they just can’t seem to put them together. Then, the show finally hits its stride and reaches its full potential.
TV Tropes even has a trope for this, called “Growing the Beard”, which gets its name from Star Trek: The Next Generation, when the show’s improvement in quality coincided with Riker growing a beard.
WKRP in Cincinnati came out strong. I believe Turkey’s Away was the 7th episode of the show and one of the most famous shows in TV history.
The Mary Tyler Moore Show hit is out of the park in the first episode. “You’ve got spunk. I hate spunk!”
Taxi was strong at the beginning but went to great with s2e3 Reverend Jim Space Odyssey. “What does a Yellow Light Mean”. They never looked back after that one.
Community announce it was something special with episode 9, “Debate 109”. Jeff & Annie debating. Abed’s predictive student Films. The show found its groove.
While I thought Community was fantastic from the word go, I’d actually argue that that Ep21 - Contemporary American Poultry was where the show hit it’s stride in making in depth layered movie references. And then, of course Ep23 - Modern Warfare pushed the conceptual ideas of the show farther.
Parks and Recreation really didn’t hit it’s stride until Season 3 when Ben Wyatt and Chris Traegar became a permanent part of the gang.
Star Trek : The Next Generation had a rough first season - but it really hit its stride in “Q: Who” the 16th episode of Season 2 - with Q’s speech " If you can’t take a little bloody nose, maybe you ought to go back home and crawl under your bed. It’s not safe out here. It’s wondrous, with treasures to satiate desires both subtle and gross. But it’s not for the timid. "
The Shield hit its stride right from the start. The first episode was one of the best of the series.
The Good Place hit its stride from the very first episode, though you may need to rewatch the first season to realize it. There were amazing things from the very start, but you may not notice then until you watch it after seeing “Michael’s Gambit.”
Over in another thread that Family Ties became what it was in the fourth episode, when Alex lost his virginity.
Of course the topic was, “when exactly was Family Ties ruined,” so sometimes the show’s stride is downhill all the way.
In the 1960s “Dark Shadows” didn’t hit it stride until episode 196 (?) when vampire Barnabas Collins was freed from his coffin and turned a six week residency into 5 years of soap opera stardom for Jonathan Frid.
It took a couple years and getting rid of the character Kirk and having Larry, Darryl and Darryl take over his business for “Newhart”.
In “Rome” it took 45 minutes and when Octavian explained to Lucius Vorenus and Titus Pullo the political situation between uncle Julius and Pompey, for it to be more than a show about women being drenched in bull’s blood with nudity and violence scattered in.
The West Wing and Buffy the Vampire Slayer both had perfectly watchable first seasons, but neither was truly great until season 2.
The Simpsons… Men of good faith can argue when the rot set in, but it had a very strong first decade, more or less. The episode where it gelled was pretty late in the first season, the one with Penny Marshall as the Babysitter Bandit. Odd, because it doesn’t feature anyone from the power plant or (if I remember correctly) Moe’s Tavern.
Star Trek TOS had two Bar Mitzvah episodes: “The Corbomite Maneuver” (which explained why Kirk was the captain) and “The Galileo Seven” (which explained why Spock wasn’t).
Saturday Night Live was lauded from day one, but most of the first season doesn’t hold up all that well, and there was a real “We don’t know what we’re doing, but we think that actually makes us better, MAN!” stink to it. Guests who should have been amazing just weren’t (Carlin, Pryor and Klein were particularly disappointing), and I only know Chevy Chase was funny because people told me so. Seasons 2 and 3 saw Chase’s departure, Bill Murray’s arrival and steady growth, and Steve Martin’s earliest appearances. They settled on a format that worked, after much trial and error, and phased out some stuff that didn’t, like the short films of Albert Brooks, Tom Schiller and Gary Weiss. Season Three had some hiccups, a number of good guest host/bad musical guest or good musical guest/bad guest host pairings (Miskel Spelman and Elvis Costello? Really? No wonder Costello was so ornery!), but really hit the mark with the Steve Martin/Blues Brothers episode on April 22, 1978–and many times afterwards.
The Good Place & Zoey’s Extraordinary Playlist both hit their stride immediately.
That went beyond “stride” to show that this show could be as good as anything TV ever did.
Crazy Ex-Girlfriend hit its stride with “West Covina” in the very first episode.