You ever have both hemispheres of your brain start arguing with each other while you're dreaming? My brain always takes a relatively normal set of events and then twist them around when I dream. And by that, I mean it starts off perfectly normal and a real thought process and then goes horribly wrong somewhere down the tracks. It's like my subconscious brain kicks in and says, "Boooooring" and starts changing things around mid-thought, the my conscious brain kicks in and says, "Wait, this makes no sense" and my subconscious kicks back in and says, "You're right, it's not fucked up enough... let's add... Zombies!" and then things go weird.