Yeah, Xander's comment to Buffy in "Empty Places" is pretty cold, but I'm not so sure it's totally undeserved. She did lead them all into a slaughter, when even a five-year-old could tell it was a trap, and plenty of people told her that. Granted, her instincts turned out to be right, but I can't really blame them for not believing her when she insisted they had to go back.