Your question: "Why do many people seem to think there is a god?"
It can be shown that religion is a learned behavior and thus people believe there exists one or more gods because they are attempting to conform to a norm that existed in the social world the were born into before they were born.
How any particular theistic religion can sometimes be demonstrated from historical evidence, but how it is that anyone came to assume there exists one or more gods cannot.
Virtually all human beings with religion for as long as we have records of it were born into a society where religion had already been invented. We are in the same situation today and it is unlikely to change.
The brain is not a truth-seeking instrument. Metaphysical explanations of sentient experience and natural phenomena have also historically been made with resort to gods, but of the case I am aware of, it was in reaction to discovery that the dominant religion of the claimants time and place did not do what it claimed to do.
In any case, there is no universal cosmic mommy-daddy or any other god and as far as anyone can demonstrate, there never has been.
In religion people believe what they want to be true, typically culturally acquired delusional claims.
A history of human thought shows that although people may believe they have acquired insight into the nature of reality and the nature of sentient experience, often what they report to be reality is a reflection of their conformity to unwarranted opinion or randomly constructed delusional schemas without any objective reality checks.
It is our natural inclination to acquire behaviors including cognitive and perceptual schemas by doing what we observe others doing, even from what we can construct mentally as models of what others might do. There is a neural basis for this, but even though such behavior is observable, until quite recently it was not known why such behavior occurs.
Neuropsychology, Mirror Neuron System:
• http://www.pbs.org/wgbh/nova/body/mirror-neurons.html
• http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0030079
Cognitive Behavioral Psychology, Observational Learning:
• http://en.wikipedia.org/wiki/Observational_learning
Social Psychology, Conformity:
• http://en.wikipedia.org/wiki/Asch_conformity_experiments
• http://en.wikipedia.org/wiki/Milgram_experiment
Likewise, due to our ample neocortex, human beings also acquire abstract schemas:
Cognitive Psychology, Schemas:
• http://en.wikipedia.org/wiki/List_of_cognitive_biases
• http://en.wikipedia.org/wiki/List_of_fallacies
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The schemas are not necessarily rational or ethical. If you would like to see that in action, watch this video:
PBS Video, Cognitive and Behavioral Psychology: "A Class Divided"
• http://www.pbs.org/wgbh/pages/frontline/shows/divided/?elq=7babe68db3c949549300dc044ba4b36c&elqCampaignId=921