I'm a fire mage, and the explosion-riddled Mythbusters show is on my DVR, so it shouldn't be any surprise that the two quests that top my nonexistent Favorite Cataclysm Quest chart are explosive and fiery. I have no idea if this is some subconscious RP coming to the surface or if I just like big booms. I'll ponder more on that later.
In Uldum, there's a quest where you turn into a fabulous, fiery gnome-killer ball
My second favorite fiery quest is in the goblin starting zone. You put on a pair of rocket boots and fly over goblin zombies, roasting them into oblivion. Hey, they're evil, okay? It's all right to giggle maniacally as you fly over 50 of them ... or more ... for hours.
What are some other fiery and explosive quests you've come across? Do you enjoy the mass slaughter of evil pixels, or do you or your character feel remorse? Do your favorite quests tend to complement your character's motif?