It's odd to think about, but according to the idea of the multiverse, even your favorite TV shows are a 100% reality, somewhere. Any sort of world you imagine in your craziest day dreams is an actual reality were people are living their own lives within that, purely because you thought it up.
Somewhere, the Doctor is saving the world.
Somewhere, Equstria exists.
Somewhere, Space Marines are fighting heresy in the name of the Emperor.
Somewhere, Hanako and Lilly are having tea, and in another universe, having tea with you.
Jason Brody is saving his friends from Vaas. Chell is traveling through the twisted test chambers. Gordon Freeman is fighting the combine. Ezio is stabbing fools in Italy.
These things ACTUALLY EXIST according to the idea of the Multiverse.
Food for thought.