Come on! How can I possibly pick one, even from my favourite show(s)?
Predictably, seeing as I cited "The Body" as my favourite episode from Buffy, I would cite Anya's speech, where an ex-demon doesn't understand why mortals have to die, as memorable. But also the scene at the end of "Smashed" where Buffy and Spike get it on while a building falls down around them. Or the last few seconds of the last episode of Season Two. Or the last few moments of Season Five.
One that I love, and show people when I want them to understand what it is about Buffy that I love, is the opening scene of an early episode in, I think, Season Five. It might be "Buffy vs Dracula." Anyway, Buffy is out patrolling in a graveyard, as usual. Along comes Riley, and she's not all that thrilled to see him - he's intruding on her turf. Then up turns Spike, who immediately susses out tension between Buffy and Riley and is amused. Some snappy dialogue ensues. Buffy more or less gets the last word and exeunt all but Spike who turns serious and says "Slayer I'm going to kill you" in some imaginative way, very sinister. Then he takes a step and falls into an open grave, cue opening credits. The timing, the fabulous unspoken tension between the three of them, the marvellous Spike, the rapid-fire dialogue, the overturning of expectations. Perfection.
Here are all the questions