Humans are not rational beings, but rationalising beings. This was the central message of one of my PGPM courses. The course was also aptly titled Intelligently Interacting with Others.
Split brain experiments have shown that our brains readily makes up stories for explaining actions that it has no previous knowledge or context of. Involuntary ones included. The brain then believes the stories to be true.
Heuristics and click whirr responses are our default operating modes. Most of the stories we believe about us are just that; stories.