Sunday marks the 25th anniversary of the premiere of Friends, but no matter how much time has passed since our first introduction to the Central Perk crew, there's still so much to learn about the show that defined one generation and is still a sensation on streaming.

Saul Austerlitz's new book Generation Friends hit shelves on Tuesday, and it is filled with lots of insider information from the making of Friends, including the kinds of details even the most knowledgeable fans can appreciate. You won't find too many scoops about the cast or how they handled their meteoric rise to fame, though; rather, it's the creatives whose stories help to paint a timeline of how the show came to be from start to finish, and Austerlitz's collection of those details makes for a compelling and informative read.

While the whole book is certainly worth checking out to find out how certain characters, settings, and creative paths changed throughout the series' run, this is the one where we pick out some of the most fun tidbits we learned from reading Generation Friends.

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1. Central Perk was inspired by a real coffee shop. Friends co-creator Marta Kauffman was in the market for a new show idea in 1993 when she happened across Insomnia Cafe, a place that reminded her of her own halcyon days of hanging out with her own close pals, including writing partner David Crane, before they made the move from Manhattan to Hollywood. Like Central Perk, the place boasted a down-home appeal, with couches and cozy chairs, and gave her an idea about what might be possible for her next story.

2. Friends went through more name changes than you ever knew. Before it would be called Friends, the then-in-development NBC series was also referred to as Insomnia Cafe (after the cafe that inspired it), Bleecker Street, NBC Pilot Which Still Needs a Title, Across the Hall, Friends Like Us, and Six of One. Luckily, none of those other mouthfuls ever made it to the airwaves.

3. Monica and Joey were supposed to be endgame. Friends fans probably already knew that the casting process for the series was very storied. Both Jennifer Aniston and Matthew Perry had other contract commitments with terrible shows that almost kept them from being available (and sparked a mini-network war between NBC and the competitors who held their contracts). Courteney Cox was chosen for Rachel but insisted she was a Monica. David Schwimmer had to be talked out of bypassing the role that was literally written with him in mind, and on and on the stories go. What fans might not have known, though, is that it was originally supposed to be Monica and Joey whose romance defined the series instead of Ross and Rachel. Joey would've been a bit smarter in this alternate reality and charmed into taking off his Casanova cap by Monica's warm personality. After Matt LeBlanc's audition proved convincing to producers, they decided they still needed to re-tool the character, and thus the Monica-Joey romance idea was scrapped (phew).

Courteney Cox, Matthew Perry, Jennifer Aniston, David Schwimmer, Matt LeBlanc, and Lisa Kudrow, <em>Friends</em>Courteney Cox, Matthew Perry, Jennifer Aniston, David Schwimmer, Matt LeBlanc, and Lisa Kudrow, Friends

4. The clapping was an impromptu addition to the theme song. Admit it. You've clapped along to that moment in the Friends theme song at least a dozen times by now because it's too catchy not to. And yet, that portion of the music almost didn't make it onto the track. When The Rembrandts recorded the number, they omitted the drum fill that'd been put into the original demo by Michael Skloff (a musician and then-husband to Kauffman), so Skloff later went into the studio and added the claps in himself instead.

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5. Ross and Rachel were supposed to accidentally kiss in Season 1. If you don't count that friendly, albeit confusing, peck at the laundromat, Ross and Rachel's first kiss didn't happen until after he returned from his China dig in Season 2, but apparently, the writers considered having them accidentally kiss during a bumpy car ride sometime in the first season — with the kicker being that it would lead to some drawn-out discussion of what it all ~meant~ as a means of dragging out their "lobster" storyline. But one writer spoke up and suggested that instead of trying to emulate Annie Hall, they take the Jane Austen approach to storytelling with the couple and have them be more star-crossed than clumsy, with near-misses that kept them at a distance but not too far to reconcile later on.

6. There's a reason the wooden post came and went. Director James Burrows helped to shape Friends into what it was at the outset, so even if the producers brought in other behind-the-lens talents as the show carried on, Burrows had a lot of say-so on the set. One of his requirements for directing an episode apparently included having the bulky divider post that occasionally stood between Monica's kitchen and living room come back whenever he shot it. So, if you're ever confused as to why the post is back in any given episode, check the director's credits and you'll probably see Burrows' name there.

7. The most high-profile guest stars had a very hard time. Perhaps the juiciest bit of Generation Friends exists in the revelation that Brooke Shields, who portrayed the fancy stalker Erica in "The One After the Superbowl," got an earful about licking Joey's hand from her then-husband Andre Agassi. Yikes. Perhaps the most interesting tidbit about all the one-off guest star experiences, though, is that Charlie Sheen got so nervous while filming "The One with the Chicken Pox" that his brother Emilio Estevez had to rub his back to convince him to continue filming.

8. There's a reason for that random Richard Branson cameo. When you have an entire airline at your disposal, you've got something to trade, and apparently Virgin Airlines founder Richard Branson wanted a role in Friends and was willing to fly the cast and crew of the show to London for free in exchange for his bit part as a souvenir salesman. That generosity helped to make the British trip possible, but it also introduced a new problem, since Branson was apparently a lousy actor.

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9. British audiences sealed the deal on Monica and Chandler. The live audience that was present during Monica and Chandler's hook-up scenes in London inadvertently became a testing ground as the producers watched for their reactions. While the couple were only supposed to have an awkward hook-up and move on, the crowd's enthusiastic approval of the situation convinced the writers that this was a couple that should last.

10. The Friends almost moved to another state. The subplot of Chandler's work relocation almost got weirder. Instead of Tulsa, the writing team once pitched having the entire group move to Minnesota for half of a season to follow Chandler on a work assignment, wherein they could enjoy the Midwest life for a while before going back to New York. Apparently, the writers were serious enough about the idea to approach David Crane, but he immediately shut it down and saved us all from "The One Where They Moved to Minnesota."

Generation Friends is on shelves now. Friends is currently available for streaming on Netflix and will move to HBO Max next year.