In the interview, the question Whedon was asked implied that even though a fan base might want characters to get together, “that often doesn’t leave the narrative with any place to go.” Whedon mentioned Sam and Diane and said:
“That’s why we had Angel go bad when he and Buffy got together. Because — and I’ve gotten into so much trouble for this phrase — what people want is not what they need. In narrative, nobody wants to see fat, married Romeo and Juliet, even if fat, married Romeo and Juliet happen to be [Dashiell Hammett’s detective couple] Nick and Nora Charles and they’re really cool and having a great time in their lovely relationship and really care about each other and have nice, well-adjusted children. Guess what? People don’t want to see it.”
Fatphobic comment aside, Nick and Nora are the protagonists of “The Thin Man” movies. The first one came out in 1934 and spawned five sequels, a series, a radio play, and more, so Whedon’s example already disproves his approach.
This makes sense for a show like “Moonlighting,” which is about a relationship, because once the pair gets together, what’s left to watch? “Buffy the Vampire Slayer,” however, wasn’t just about Buffy (Sarah Michelle Gellar) and Angel (David Boreanaz) and the whole will-they-won’t-they of it all. It was also about fighting monsters, high school/college friendships, a mentor dealing with his own past, a young woman who is trying to navigate being a hero, unlike the ones she grew up reading about, and trying to have a normal life as well.