One of the most jarring accusations by atheists is that believers are suffering from some kind of delusion. Believers, they suggest, are merely looking for a comfortable father-figure. However NYU psychology professor Paul Vitz has a rather fascinating rebuttal to these accusations, entitled "The Psychology of Atheism."
It occurs to me that because we are subject to our parents when we are young and helpless, for good or ill, our relationship with them affects how we relate to God. Early abuse leads one to expect those with power to abuse it. I find it telling that children are born expecting their parents to be infallible. One might posit that it is an early breaking of this trust that leads to a lack of faith in God.