Who is God?

This is the second snippet from The Shack. God is having a discussion with Mackenzie about who/what God is:

“I am what some would say 'holy and wholly other than you.' The problem is that many folks try to grasp some sense of who I am by taking the best version of themselves, projecting that to the nth degree, factoring in all the goodness they can perceive, which often isn't much, and then call that God. And while it may seem like a noble effort, the truth is that if falls pitifully short of who I really am. I'm not merely the best version of you that you can think of. I am far more than that, above and beyond all that you can ask or think”— The Shack, page 97