Stunt casting stumbles (Jean-Claude Van Damme, Charlie Sheen) aside, the second season was a very good year. Ross and Rachel were the engine that drove the season and produced some of the series' most monumental episodes, including "The One with Ross' New Girlfriend," "The One Where Ross Finds Out" (with R & R's first kiss), "The One with the List," "The One with the Prom Video," and "The One Where Ross and Rachel... You Know." But this was not the only significant story arc. Enter--and, in the bittersweet season finale, exit--Tom Selleck as Dr. Richard Burke, the family friend who becomes Monica's lover. Joey finds success (albeit short-lived) as Dr. Drake Ramoray on "Days of Our Lives" and moves out. Future Emmy winner Lisa Kudrow's best season is to come, but, as Phoebe, she makes the most of some memorable subplots, including her shocked discovery of sad movie endings she had been shielded from, her dispute with Ross over evolution, and her channeling of an elderly woman who died on her massage table.

Friends' peerless writing staff really spread the wealth in the pivotal third season. Each of this seamless ensemble's cast members was given a story arc that deepened and enriched their characters. Most devastatingly, Ross and Rachel's romance is torn asunder by Ross's jealousy (not to mention his one-night stand while the couple are, now famously, "on a break"). Phoebe is reunited with her half brother (Giovanni Ribisi) and meets a family friend (Terri Garr; inspired casting) who drops a Darth Vader-esque bombshell about Phoebe's parentage. Monica begins the season reeling from her breakup with Richard, but rebounds with millionaire Pete (Jon Favreau from Swingers). Chandler is driven to increasingly hysterical attempts to "go through the tunnel" and commit to his relationship with Janice (Maggie Wheeler). And womanizer Joey reveals his soulful side when he falls for an initially contemptuous theatrical costar. Also lending memorable support are Alison LaPlaca, as Rachel's self-absorbed new boss, and an Emmy-worthy Ben Stiller as Rachel's new boyfriend whose volcanic temper only erupts in front of Ross. Among the A-list cameos, Robin Williams and Billy Crystal are woeful, but more memorable is Isabella Rossellini, whom the hapless Ross meets just after crossing her off his "freebie list" of celebrities Rachel would allow him to sleep with. Other classic episodes include the season-opener, "The One with the Princess Leia Fantasy" and "The One with the Flashback," which offers some provocative near-couplings between Monica and Joey, Ross and Phoebe, and Chandler and Rachel. Add a chick and a duck ("The One with a Chick, and a Duck"), and you have a benchmark season in this irreplaceable series.

Friends' fourth season, one of the very best and most consistently satisfying, begins with Chandler urinating on Monica's leg to relieve a jellyfish sting. It ends with the two in bed and in lust. In between are several benchmark episodes and rich, character-enriching plot developments that keep this series from coasting on comfort level. Phoebe agrees to become a surrogate mother for her long-lost brother. Chandler "crosses the line" after falling in love with Joey's girlfriend, and is forced to spend one memorable Thanksgiving in a box. Rachel desperately pursues the recently divorced Joshua (then real-life squeeze Tate Donovan). Joey and Chandler trade spaces with Monica and Rachel, and then, with provocative (albeit offscreen) sapphic compensation, return to their humble abode. And Ross meets the warm and wonderful Emily (Helen Baxendale), setting the stage for a London wedding and classic season finale that revitalizes our rooting interest in the whole Ross and Rachel thing. Especially jolly good in this two-parter are the scene-stealing British character actors, including Hugh Laurie as the unfortunate airline passenger seated next to Rachel as she wings toward London to tell Ross she loves him, and Tom Conti and an absolutely fabulous Jennifer Saunders as Emily's squabbling parents. --Donald Liebenson

Divorce number 2 is immediately on the cards as the fifth season opens with "The One After Ross Says Rachel." As of this point, Ross's character undergoes some extreme personality changes. His incessant whining drives all the Friends to distraction, especially in "The One Where Ross Moves In" with Chandler and Joey. Later things get uncomfortable both at work and at home when he goes through a period of rage. While all this downplays his failed relationship with Rachel, the real idea is to allow focus on the secret pairing of Chandler and Monica after a night of passion in London. This made for a return to the show's appealingly silly atmosphere as poor Joey is caught in the middle of everyone's secrets. Building to "The One Where Everybody Finds Out," the silliness pauses for some genuinely touching interplay between Perry and Cox. The previous year's semi-serious thread about Phoebe's birth gets forgotten fast: to distract the viewer she's introduced to Gary (Michael Rapaport) in "The One with the Cop." This leads to some hilarious parodying with Phoebe interrogated about apartment hunting, and the guys excited and then scared in "The One with the Ride-Along." She's more than over him by the time of the two-part finale, "The One in Vegas," though, especially since she missed out on London. Just in case fans thought Chandler and Monica had permanently stolen the spotlight, a cliffhanger shocks expectation again with Ross and Rachel bursting out of a chapel....

Between Friends' fifth and sixth seasons, Courteney Cox and David Arquette were married, leading to "The One After Vegas" adding "Arquette" after everyone's title credits. Unfortunately, on-screen it's divorce time again despite "The One When Ross Hugs Rachel," since he secretly tries avoiding an annulment of their accidental marriage. Far more out in the open is Chandler and Monica's relationship. Moving in together creates lots of fun as the others move back and forth into each other's apartments. It also leads to Joey finally showing a tender side toward temporary roommate Janine (Elle Macpherson). More fun came from Ross trying to teach everyone the mental discipline Unagi, popping ridiculous moves with Monica for their childhood dance routine and having a fluorescently dazzling smile in "The One with Ross's Teeth" (also featuring a near-silent cameo from Ralph Lauren). Far more talkative was Reese Witherspoon as Rachel's (Jennifer Aniston) sister--another temptation for Ross. What they briefly had wasn't as complicated as later in "The One Where Ross Meets Elizabeth's Dad," who turns out to be an Emmy-winning Bruce Willis). The fans' need for love interest and continuity had established the seasons' format now. Another two-part finale offers jeopardy--then resolution--from Tom Selleck's Richard in "The One with the Proposal" between Chandler and Monica.

Lots happened behind the scenes between seasons and early on in the seventh year of Friends, leaving audiences speculating this might be the last. But the real news (allaying fans' fears) was NBC's expensive renewal of the cast for two years. On-screen, at least there was Chandler and Monica's engagement lasting the whole year, despite predictable ups and downs. By the time we finally get to "The One with Chandler's Dad" (Kathleen Turner!), it seems inevitable that the two-part finale will be an insane mess--but with a happy-ish ending. Sure enough, "The One with Monica and Chandler's Wedding" features Gary Oldman joining in the chaos as Chandler repeatedly goes missing. But perhaps the most telling installment of this weirdly atmospheric year was "The One Where They All Turn Thirty." It suggested that maybe the Friends were all getting too old to carry on living their frivolous lives the same way after all. --Paul Tonks