When god created the world, he wanted to make a people in his image. This people is known as the Real Humans. He gave them three deciding traits to set them apart from the rest of his creation:
Curiosity made them venture out into the world, to discover what god had created. They also tried to think of new ways to see what they already knew.
Privacy made the Real Humans think a lot in their own minds. It made them unwilling to share all their thoughts with everybody, and also made them unwilling to spend all the time in the presence of reality.
Creativity was the final spark. This made the Real Humans so similar to god that they started to act like him: Every Real Human created his own set of existences. Every existence its own universe with everything that belongs to it.
These co-existing existences were the status quo, until one day, the existential crisis began. Since then, existences started colliding, breaking into each other. Now, separate existences are not as separate anymore.