9. As You Were (Season 6, episode 15)
‘As You Were’ was the episode that saw the brief return of Riley alongside his new wife Sam, whose role didn’t really impact the episode that much, if I’m being honest. Riley returns to ask Buffy for her help in tracking down a demon black market dealer known as ‘The Doctor.’ Basically, it turns out ‘The Doctor ‘ is Spike. During his visit, Riley also discovers that Buffy and Spike have been having an affair. The episode in some ways just acts as the final goodbye to Riley and sets the mood for the next episode: ‘Hells Bells,’ a.k.a. Anya and Xander’s wedding.