Way back in time when we were scribbling on cave walls and dragging women around by their hair, man worshipped animals.
As soon as man developed more intelligence, started painting buffalo on cave walls and dragging women around by their ankles, he started to reason that animals were better to eat than to worship.
Quite a reversal of culture, one might think, so man simply reversed the word DOG to become GOD.
The only problem was that man didn't think it out too cleverly because there was nothing "actual" to fill the description of God so he just let it slide and gradually he started making up stories around the campfire whilst consuming copious quantities of hemlock mead about this God who talks to him.
And things haven't really developed very much since then, have they?
Oh, except that man now makes crappy selfies with his iPhone and drags women around in 4WD pickups.