No, it's none of the above. It's her voice. It's that awful, rasping, screeching bellow. It's the way she draws out the word 'betray' that wasn't so bad the first time I heard it but let me tell you three wipes in and I was ready to turn off the sound effects entirely. I want to kill her every week not because there is loot to be had, but so that I do not have to listen to her anymore.
On the other hand, back in the days of Blackwing Lair I begged my raid leader to let me trigger the Nefarian event, just because I really wanted to hear him talk. I forget the exact number of times we wiped on Nefarian before finally killing him for the first time, but the silky way in which he said "Let the games begin" made it a little easier to take. There are other bosses and encounter voices I love -- nobody can forget Millhouse Manastorm, he of the infamous "I'm gonna light you up, sweet cheeks!" I always loved the voice of C'thun. The first time I stepped foot into AQ40 and heard that eerie, low voice from out of nowhere, politely informing me that my friends would abandon me and that I would die, I nearly yelped aloud.
But Sindragosa. Ah, Sindragosa, you have reached a level of irritation with me that rivals even Jaina Proudmoore's incessant sobbing or Kael'thas' never ending bantering in Magister's Terrace -- which now takes longer to listen to than it takes to kill him. So how about you guys -- who's tops on the voice acting in your opinion? Who do you love to hear every time you kill them? Whose voice makes you reach for the mute button?