When I saw patchnotes about dismissing shop items decreasing lovelyness I knew I had to give Cthuluhu Priest a go. If you don't know offhand, Priests of Cthulhu gain cultist followers (and the EXP they would've given) from the floor's population based on how negative your lovelyness is. Given the plentiful amount of merchandise to wreck in every shop I was able to reach 100% hate after about 3 shop visits.
Having the entire population of every floor join me was both awesome and awful.
As one might expect, having the only hostile enemies (for the most part) be bosses trivialized much of the game. However, the reason you don't want to try drowning Maevalin with the entire population of the dungeon are performance related. In order to keep the game at playable framerate I had to frequently find ways to cull my followers. For better or worse, I neglected picking up a good friendly fire spell.
The closest I ever got to dying was stepping on a hidden trap and eating a mouthfull of Charged Bolts. Thankfully I had a fat health bar and my electricity resist was capped at that point. But despite that I still went down to around 4% health instantly. Which gave me second thoughts about how useful Quon's curse of trapping the exit stairs was for my situation.