I have been watching bits of Season 7, and have to pause and commend Sarah Michelle Gellar's facial journey in this scene in Beneath You. This is where Buffy accuses Spike of not changing, and Spike doubles down on it. She has so many layers to her micro expressions, it's insane.
The "how could you?" mixed with digust
To the vindicated rage after throwing Spike to the floor:
And finally, my favourite the vulnerable defiance she has as she gets into James Marsters' face like a threat:
The vulnerability is such an interesting addition to the defiance and threat - because you have seen Buffy being threatening and defiant in so many other contexts, but the vulnerability of her eyes say so many things.
It's true that Buffy doesn't get to process the events of Season 6 as much in Season 7 writing wise, but Sarah shows a whole story with just her face, minimal dialogue and it ends with the church scene. Beautiful.