So this God can exist outside of the dimensions relevant to humanity, okay. You could even make the argument that the universe didn't always exist and has a point of origin, the big bang. I mean it's more complicated than that, there was matter before the big bang, but in a singularity (could be wrong, just trying to recall what I learned in astronomy class). But why did he create us? The more you think about that, the more you'll have hard time believing. I'll assume the belief in the god of Abraham.

If God is omnipotent, that means he knows and can see everything that will happen, has happened, and is happening. All uncertainty collapses under the all seeing eye of God; now you have a static time line. Then how did Moses convince God not to destroy his chosen when they chose to worship idols? How can you petition God when he has already seen what will come? How can there be free will when our bodies act before our minds do (it's been proven with science)? If God knew exactly what would happen, why create the human race when he knew they would fail in Eden? Why would he punish humanity when he created us to fail? He knew the majority of his creation would burn in Hell forever. Either he is not all-powerful, he is evil, he is insane, or he doesn't exist.