"God is a metaphor for that which transcends all levels of intellectual thought. It's as simple as that."- Joseph Campbell
The concept here is the same as the "god of the gaps" - all the things we don't understand or cannot comprehend - i.e. the gaps in our knowledge we believe to be God's work, a sort of cosmic catch all for explaining things we don't know about. To other people god is a comfort blanket - if you are down on your luck, or have some unexpected good fortune we often attribute it to god. How many times have you uttered the word "thank god for that" when something works in your favour? Or heard someone thanking god for saving them from a hurricane or perhaps blaming god for their misfortune?
In addition to the "God of gaps" notion I would contend more precisely that God has to do with anxiety about what consciousness really is. Science tries to tell us that it is simply a "Newtonian" physical process going on in the mechanics of our brain chemistry and electrical activity. We all can reason as well as feel innately that this is really so beyond insufficient to explain the situation. We are not just meat robots. This is what I would say is the biggest "gap" of all because this is the one that is most personal to each and every one of us. There is more in heaven and earth than can be dreampt of in our imaginations, paraphrasing a quote from Hamlet.