Why do some people claim to know the god they believe in exists, despite having no evidence for this claim?

Note: logical fallacies like appeal to ignorance, negative proof/burden of proof, and special pleading are not evidence; neither are quotes from the bible, insults, claims that I already have evidence, links to websites that allegedly have evidence, personal experiences, self-fulfilling or vague prophecies matched against millennia of history, or anecdotes which have a natural explanation or no supporting evidence.