it suddenly strikes me that both Xander and Willow would probably shocked to see either one of them act that way.

I'm quite disappointed that Xander and Willow never got to meet immature Giles in Band Candy. Also it would have been great to have an episode about Buffy forgetting three years of her life during S2, and Xander and Willow get to meet shallow Buffy -something like the novel Remember Me?