Another thing I was thinking about recently: the Scoobies' and Potentials' mutiny against Buffy in late Season 7. I used to think they were just being ungrateful dicks, but now that I think about it, it wasn't completely unjustified.
Let's face it: most of Buffy's plans were just plain awful and ended with a lot of people getting hurt needlessly, and her defense of her those decisions ("I'm the Slayer, do it my way because I say so") is not convincing. Case in point: in "Empty Places," she immediately wants to attack Caleb again, literally right after everyone got out of the hospital after they fought him and lost the first time. Not to mention the fact that the others warned her that it might be a trap, but Buffy didn't listen.
Of course, their decision to appoint Faith the leader over Buffy just because she was the only other full-fledged Slayer was a pretty stupid decision as well; Faith had no leadership experience, and both Giles and Willow were much better candidates.