If my dreams were real, it would be the end of the world as we know it.
Me and my subconscious have been at "war" with each other for a few years now, because I don't regularly dream at night and I tend to daydream more often, which is the source of my fiction writings. I ocassionally have some pretty messed up dreams, and if any of them we're to be real, that would spell disaster on a cataclysmic level.
Oddly enough, I had been working on a fictional work which various characters, each hailing from their own fictional world, meet in one new world for which the individual characters' dreams shape the landscape of the world.