Buffy the Vampire Slayer (season 6)

• Sarah Michelle Gellar as Buffy Summers
• Nicholas Brendon as Xander Harris
• Emma Caulfield as Anya Jenkins
• Michelle Trachtenberg as Dawn Summers
• Amber Benson as Tara Maclay
• James Marsters as Spike
• Alyson Hannigan as Willow Rosenberg

* ^ Benson is only credited in the opening credits for one episode, and is credited as a guest star for all her other appearances.

• Marc Blucas as Riley Finn
• Dean Butler as Hank Summers
• Kristine Sutherland as Joyce Summers
• Andy Umberger as D'Hoffryn

The sixth season of Buffy the Vampire Slayer coincided with the third season of Angel. With this season, Buffy switched networks from The WB to UPN, while Angel still remained on The WB. Because they were on competing networks, there were no official crossovers. At the time, WB Entertainment President Jordan Levin stated "There will be no crossovers between Angel and Buffy. I think it's more important, in the long term, that Angel really establishes itself as a world that obviously comes from the same mythology, but operates with its own set of principles, guidelines and characters, and really establishes itself independently from Buffy."[23] Although there are no distinct crossovers where characters appear on the other shows, there are moments where characters are mentioned or interactions between the two series' characters occur off screen.

At the end of the Angel episode "Carpe Noctem", Angel (David Boreanaz) receives a telephone call in which Willow tells him Buffy is alive. Buffy then receives a call from Angel at the end of "Flooded", and immediately leaves to meet with him. Although the phone call scenes happen on screen, neither Willow's side on Angel nor Angel's side on Buffy is shown. The scene between Buffy and Angel also happens off screen, but is described by them in the following episodes.

Due to the crossover embargo, this is the only season of Buffy in which Angel does not appear.

"Once More, with Feeling" was nominated for a Hugo Award for Best Dramatic Presentation and for a Nebula Award for Best Script.

"Once More, with Feeling" received positive praise from media and critics when it aired, during overseas syndication, and in reminiscences of the best episodes of Buffy after the series ended. Although Salon.com writer Stephanie Zacharek states "(t)he songs were only half-memorable at best, and the singing ability of the show's regular cast ranged only from the fairly good to the not so great", she also asserts that it works "beautifully", paces itself gracefully, and is "clever and affecting".[30] Tony Johnston in the Herald Sun writes that Gellar "struggles on some of her higher notes, but her dance routines are superb, Michelle Trachtenberg's Dawn reveals sensual dance moves way beyond her tender years, and James Marsters' Spike evokes a sort of Billy Idol yell to disguise his lack of vocal proficiency [...] The rest of the cast mix and match like ready-made Broadway troupers." Johnston counts "I'll Never Tell" as one of the episode's "standout moments".[31] Connie Ogle in The Miami Herald calls the songs "better and far more clever than most of the ones you'll hear on Broadway these days".[32]

Writers agree that the episode was risky and could have failed spectacularly. Jonathan Bernstein in the British newspaper The Observer writes "What could have been, at best, an eccentric diversion and, at worst, a shuddering embarrassment, succeeded on every level [...] It provided a startling demonstration that creator Joss Whedon has a facility with lyrics and melody equal to the one he's demonstrated for the past six seasons with dialogue, character and plot twists. Rather than adopt the 'Hey, wouldn't it be wacky if we suddenly burst into song?' approach practiced by Ally McBeal, the Buffy musical was entirely organic to the series' labyrinthine progression."[33] Steve Murray in The Atlanta Journal-Constitution characterizes the episode as "scary in a brand-new way", saying "Once More, with Feeling" is "as impressive as Whedon's milestone episodes 'Hush' and 'The Body'"; the episode is "often hilarious", according to Murray, and acts as "(b)oth spoof and homage, [parodying] the hokiness of musicals while also capturing the guilty pleasure and surges of feeling the genre inspires".[34]

Scott Feschuk in Canada's National Post states that the episode "conveyed the same sense of rampant, runaway genius—the rare fusion of artful storytelling and ardent entertainment, a production capable of moving viewers to tears or to an awestruck rapture".[35] Writing in the Toronto Star, Vinay Menon calls "Once More, with Feeling" "dazzling" and writes of "Joss Whedon's inimitable genius"; he goes on to say "(f)or a show that already violates conventions and morphs between genres, its allegorical narrative zigging and zagging seamlessly across chatty comedy, drama and over-the-top horror, 'Once More, with Feeling' is a towering achievement [...] The show may be anchored by existential weightiness, it may be painted with broad, supernatural brushstrokes, but in the end, this coming-of-age story, filled with angst and alienation, is more real than any other so-called teen drama [...] So let's add another line of gushing praise: 'Once More, with Feeling' is rhapsodic, original, deeply affecting, and ultimately, transcendental. Quite simply, television at its best."[36]

Season six of Buffy the Vampire Slayer is the most controversial among its ardent fandom because it was dramatically darker in tone than previous seasons; it has been called the show's "most hated season".[37] Syfy Wire stated that the show's sixth season "has always been a thorn in its fandom's side. It was a little darker, a little meaner, and a little too different from what came before for the entrenched base to accept."[38]

Joanna Robinson of Vanity Fair wrote on the 20th anniversary of the show's premiere that season 6, "a dark, unpopular chapter in the show's seven-year run...once its most hated - has become its most important." Robinson praised the introduction of the Evil Trio, the much-maligned "Big Bad" villains for season 6, as presaging the later trend of "entitled, misogynistic rhetoric that rose to the surface during the Gamergate culture wars of 2014, and has seemingly infiltrated everything since—the 2016 presidential election included." She concluded, positively, that "It may lack some of the trademark zip of the show in its prime, and critics of the Dark Willow storyline, in particular, are not wrong in their concerns. But with the luxury of historical context, Season 6 of Buffy carries more powerful resonance than any other moment in the show's history."[37]

About the season's criticism, Joss Whedon says: "I love season 6. It’s really important. But it was a very stark thing to do. It wasn’t just putting Buffy in a very bad, abusive, weird relationship, it was some sort of an end to magic. For me because childhood is so rich with metaphor, a lot of it had to do with leaving that behind. Instead of a bigger than life villain, we had the nerd troika. Instead of drinking blood and doing spells as a sexual metaphor, we had sex. Things became very literal and they lost some of their loveliness. I still think that a lot of the best episodes we ever did were in season 6. I don’t agree with the detractors, but I understand it."[39]

Acting as showrunner for season 6, Marti Noxon received the brunt of fan criticism, eventually stating in 2018 that she felt parts of season 6 "went too far." She elaborated that "We pushed into some categories that almost felt sadistic and that Buffy was volunteering for things that were beyond just “bad choices” and were almost irresponsible for the character. That may have to do with my own history...And I think that killing Tara was — in retrospect, of all the people, did she have to die?"[40] She explained her rationale for taking Buffy in a darker direction, stating that "...I was really vocal about wanting Buffy to make some bad mistakes. My argument was that, when we become young women, especially if we're troubled or haunted by something, that can lead us to make some bad choices, especially in the area of romance."[40]