Having paid interest in religious debates over some time now, reading books, trawling webforums, YouTube and the like, I feel I am familiar with the common "bastions" on either side of the aisle concerning religious beliefs and convictions - ACA included, of course.
I feel however there is one observation that hasn't gotten much attention in the usual "soup" of various arguments - which is the following:
At some point, man gained the cognitive ability to form existential thoughts. He might not have been able to articulate them very well, but there must have been an incident in time where the caveman gazed upon the stars and wondered "Why am I here? I feel so little compared to the rest of this world. What happens when I die? Who made all of this? What is the meaning of our existence?", and so on and so forth.
The fear of meaningslessness and nothingness must be unbearable.
I'm convinced that man's ability for existential thought processing is the very foundation for believing in a supreme being, and then consequently: God/Allah/Jahveh/Vishnu, et al.
The coincidental nature of which one you end up adhering to, in that it's mostly based on where you happen to be born or grow up, has been duly pointed out by Richard Dawkins.
On that note, I'll finish up with one of my favorite quotes from Bill Maher:
"religion is the bureaucracy between man and his god."
This is an interesting position I have not heard before. Of course, as an atheist I don't see the connection between mankind's mental development and there having to be a higher intelligent power to enable that. I am sure that there are many animals that recognize the sun as a big ball of light coming up and going down int he sky. I'm sure they see the stars and recognize them as tiny lights in the sky. Other animals need no further explanation of these natural phenomena, their brains haven't developed the necessity.
Eventually early man was able to think more critically about our surroundings and immediately we used supernatural explanations to answer our own questions and to avoid confronting the uncomfortable meaninglessness of our existence. This eventually evolved into believing in gods.
An interesting question to ask: From what necessity did humans develop a deeper mental capacity?
I would propose that early man-like beings who could think more critically about the "big questions" in life also would have a brain that would help them survive more. The more we could think, the more we could survive. The more we could survive, the more scary these big unanswerable questions became, the more we needed to fill in the blanks with supernatural explanations.
Therefore, the idea of a higher power is man made.