Or, an Unreasonable Reason to be Reasonable.
Whatever you do, Don't believe in the being I am about to describe to you. your immortal Soul (or something) may depend on it! (probably not)
You see, the universe, Earth, all living things, all human beings and all the works of said beings- all is the creation of one, all-powerful being! Whether it was all created a few billion years ago or five thousand years or twenty seconds doesn't really matter- this being made sure when he/she/it created it all that it left no specific evidence of itself in the creation! Evolution? Ha! probably never happened, all those dinosaur bones and DNA and other mountains of evidence were all manufactured just to make people believe evolution. The same is probably true of things like the sun and various other celestial bodies, and hey, probably the ground beneath our feet a few miles down. Even if this being has never directly manufactured a human sensation, or created human beings full grown with memories of events that never really happened, It could easily be just around the corner, just out of sight, manufacturing everything we see, feel or otherwise sense indirectly about the world beyond our immediate vicinity. Such is the nature of Ungod, for that is what we shall call our omnipotent overseer. But why does It do all of these things?
It's all a big, elaborate test! Ungod created all us humans, gave us free will (or made us think we had it) and then set up this huge elaborate lie for us to live in. It didn't do this to use our brains as batteries, It could have made some nice nickel cadmium ones for that. It sure didn't do it to make more beings in it's own image- we don't look, act, think, or even smell like Ungod. It was all a test, to see who would believe the lie! To see who would fall for it, and come up with theories of relativity and evolution and gravity- all things that don't really exist. To see who would ignore the lie that UnGod provided and come up with their own more interesting lies. To see if anyone would see through everything and determine the existence of UnGod, despite the absolute absence of evidence.
Who passed the test? Well, it's obvious, isn't it? The people who believed the lie. The ones who used their little brains and the evidence of the world they were presented with and came up with explanations for it. The world UnGod built around us was absolutely internally self-consistent, so any rational being would have to believe the lie It told. The ones who ignored the world they saw and made up their own little lies UnGod considered failures. The ones who actually stumbled, utterly at random, upon the truth? These UnGod might laugh at, if It had a sense of humour, but for them the fate was the same as those who made up their own lies- because after all, if there is no evidence for what you believe, it might as well be made up.
What fate awaits us all? Well, those who took the world as they saw it and ran with it, in other words, the atheists, will spend their afterlife in rather surprised bliss. Everyone else, all those who made up and believed the much less consistent mortal lies, will spend their afterlife in even more surprised tedium, having to listen to an eternal lecture from UnGod about how dumb they were to believe any lie but It's own.