Where is Joyce? Why isn't she at home handing out candy?
What the hell brought Ethan to Sunnydale on this mischief? His role in later eps isn't so difficult to extrapolate. But in Halloween, it's baffling. Sure, he worships Chaos, and okay, maybe the Hellmouth had allure for a pilgrim of the damned, but why open up a costume shop--which implies planning ahead to some extent--and turn a townful of kids into demons? What does this get him, in the short or long term? Did he know Giles was there? Was it deliberate provocation in the hopes that his old mate would look him up for some nookie? (And where does he go between The Dark Age and Band Candy? He isn't still in the area all that time, is he?)
Xander, re Angel and Buffy: "Give it up, Cordy, you're never going to get between those two."
Oz in the British van. Ha. I'd heard about it on one of the commentaries, but only now noticed it for the first time.