Just a little thing I'm doing out of curiosity. So, which mob do you like to face the least?
For me, its zombies. I hate those guys. High health, high damage, and an immunity to poison means there is no easy way to approach them, neither physical nor magical.
I usually don't even bother with higher level ones; they may be still weaker than bosses, but not by much, and they're naturally less rewarding.
They do make good IMAWAL-fodder though....