I actually really like and admire Joss's unpredictability, however, there have been a few moments where I've really, REALLY been upset, most notably the way he ruined Cordelia's character, and the whole Connor/Cordelia thing in general.
Cordelia was one of my favourite characters; to see her growth from vapid, shallow bitch (I liked her like that too, don't get me wrong!) to absolutely decent human being was so epic, and to have that just ripped up really disappointed me.
Tara's death in Seeing Red doesn't actually make me all that mad -- of course I wish she could've stayed, but her death being the catalyst to DarkWillow's rampage, plus all the angst it brought, I thought it was good for the series as a whole. Maybe I'm a masochist, lol!
However, one thing that does make me mad at Joss is in that ep when Spike attempts to rape Buffy. I know he doesn't have a soul, and it was also an important catalyst in Spike seeking redemption, and his soul, but it was so painful to watch :/
