As Francis Bacon once said, Man prefers to believe what he prefers to be true.
So the challenge for us is to understand that truth is separate from the self, and to remove our passions from obscuring our vision of the truth.
An example of failure to meet this challenge is found in Freuds preference to believe there is no Moral Law. He preferred to follow his own rules.
Interesting to note: Freud hated both absolute moral law and the aesthetic appreciation of music.
Anyway, Freuds rejection of God was founded in his desire to make up his own rules. In my opinion, this is the most common thought process giving rise to atheism specifically and to naturalism more broadly.
Freud thought that God and religion were ‘illusions’, and didn’t like Jung’s interest in religion, mysticism, and the paranormal.
Jung thought Freud was neurotic.