It all starts early on in childhood, doesn't it? You know, the age-old tradition of bringing kids into line by telling them about the ever elusive and perennial fairy story heroes.
"If you put your tooth under a glass and be really good, the Tooth Fairy will put some money under it while you sleep."
"Santa Claus will slip down the chimney and bring you some gifts, but only if you behave yourself."
"Jesus was born to a virgin who was married then died and turned invisible, then he evaporated into heaven and you will get to go there with all your family but only if you believe this. "
It's all a lot of fun when you are young, innocent, and naive and even later in childhood when we know it is all a load of bovine excrement, we jokingly go along with the stories as a form of manipulation in order to get the Xmas gifts and money under the glass.
As for the Jesus example, we just go along with it in order not to get a spanking from our manipulative parents or Sunday school teacher. So, we all grow out of it and go on to lead normal lives.
There are some people however who have a psychological condition preventing them from developing as normal, knowledgeable, and aware. In fact, these people cling onto their infantile fairy tales and develop a craving to absorb even more absurd and morbid fairy tales.
The over-riding condition for this sort of bizarre, unrealistic, and contrived obsession, of course, Is called delusion. But could it be that religious nuts just simply never grow up?