Why are you chasing the idea of the existence of a God?

[robvalue]

The inability of theists to agree on even the most basic qualities is good evidence that it does not relate to a single, real entity. It's never been demonstrated that any of these versions do anything at all outside the mind of the theist. They generally do everything you'd expect, such as agreeing with them on every subject, and sharing their knowledge.

I'm not inclined to agree that this is a substantial issue.  We have concepts without clear delineation that are nonetheless valid concepts, nobody complains that chairs don't exist because there is no all encompassing definition for what a chair is.  We acknowledge the fallacy of the beard, that sometimes there aren't clearly definable distinctions without throwing up our hands and claiming that therefore all things belong in the same category.  The concept of a beard doesn't become invalid simply because there is no clear dividing point.  Language is by its nature slippery and trades on ambiguity for its power.  That there is no clear and unambiguous definition of God even if true is a question of epistemology, not of whether such an ill-defined entity does or does not exist.

Sure, but there is not supposed to be just one chair that exists. Also, we have innumerable real examples of chairs that we can point to at any time. There is supposed to be just one God, according to most religions, yet they each describe God with even less consistency than people would describe the qualities of chairs.

I can say chairs are something useful for sitting on; I'm not sure there's even one statement that could be made about God that could be said to be universal among theists. The nearest is, "Our creator". But the word God always carries way more baggage than that; baggage which they can never agree on. And even then, we have pantheists and such who use "God" to mean something which isn't even a creator.