Of all the great things about television, the greatest is that it’s on every single day. TV history is being made, day in and day out, in ways big and small. In an effort to better appreciate this history, we’re taking a look back, every day, at one particular TV milestone.

IMPORTANT DATE IN TV HISTORY: November 6, 2001

PROGRAM ORIGINALLY AIRED ON THIS DATE: Buffy the Vampire Slayer,”Once More With Feeling” (Season 6, Episode 7) [Watch on Netflix]

WHY IT’S IMPORTANT: Opinions on the sixth season of Buffy the Vampire Slayer vary — it was the show’s first after the move to UPN; Joss Whedon’s attentions were elsewhere, as he was working on the Firefly pilot — but there is near-total agreement that “Once More With Feeling” is the season’s highlight, and one of the best episodes of the series. The fact that it’s a musical contributes to the rewatchability of the episode, and I can’t imagine I’m alone in having watched it many, many times over the years.

What remains so impressive about “Once More With Feeling” is the scope of the ambition. It’s not like no one had done musical episodes of non-musical series before, but they were nowhere near as commonplace as they’ve become now, and it’s Buffy that made sure the coast was clear. What’s more, rather than simply toss off a standalone episode removed from the main storylines of the season, “OMWF” dealt directly with not only major story lines but served as a major turning point for almost all its characters. Buffy and Spike finally kissed. Tara found out Willow had been enchanting her. Xander and Anya expressed grave doubts about their impending marriage that would pay off later on in the season.

The singing isn’t uniformly great (aw, Alyson Hannigan), but that’s part of the charm. And it fits with the episode. The singing demon that comes to Sunnydale doesn’t make everyone in town good at singing. It just compels them to sing. And then, of course, there’s how creative the actual songs are. Diverse and inventive and funny and sad. The score overall is a little patchworky, with each song existing as a different kind of experiment, but they make for some spectacular moments. Particularly when the musical motif is played for self-aware laughs.

The episode is a deserved fan favorite, and perhaps the last truly classic Buffy episode. Even if you didn’t like the bummer turn that Season Six took, “Once More With Feeling” made it worthwhile.

Joe Reid (@joereid) is a freelance writer living in Brooklyn. You can find him leaving flowers for Mrs. Landingham at the corner of 18th and Potomac.