In every Diablo game I've had a couple of mobs I hated from the bottom of my soul. In Diablo 1 it was the Soulburner (totally magic immune in Hell), and in Diablo 2 it was the Gloams and Dolls. After having played Diablo 3 pretty casually so far I can already tell which mobs are going to be my bane. It is the Soul Ripper. So what is your most hated monster?