I get that, but that too is a lazy argument taken from a Philosophy 101 course (i.e. "if God is all-mighty could he create a stone even He cannot lift?"). My rebuttal is, "what created the universe, it's here so how did it come into being, the Big Bang is generally accepted to be the start but what was before the Big Bang..." etc.) Yet we are in fact here (or we think we are).
An accepted way to prove the existence of something is to prove it's effect on the things around it without directly observing the thing or phenomena in question. We see it all the time when studying astronomy.
Numerous studies have shown that people who regularly attend church (of any denomination) are generally happier than those who do not. I'm talking populations, not individuals so please don't state how noble and happy you are because there's plenty of folks like that in every camp. Population-wise, believers lead happier lives...what's the root cause? Most likely it's belonging to a group of like-minded people who support each other and go good acts within their communities but could it be that God is acting somehow on their lives? Even if it's a placebo effect, it is a good thing.