Leonard Mlodinow writes in Subliminal: How Your Unconscious Mind Rules Your Behavior:
We all make personal, financial, and business decisions, confident that we have properly weighed all the important factors and acted accordingly – and that we know how we came to those decisions. But we are aware only of our conscious influences, and so have only partial information. As a result, our view of ourselves and our motivations, and of society, is like a jigsaw puzzle with most of the pieces missing. We fill in blanks and make guesses, but the truth about us is far more complex and subtle than that which can be understood as the straightforward calculation of conscious and rational minds.
What I keep saying. We’re not 100% rational, to put it mildly. It’s rational to be aware of that, to realize it applies to ourselves as well as other people, to realize it applies to us and to others, to try to be aware of what follows from that. It’s not rational to expect 100% rationality from other human beings. It’s not rational to assume that one is oneself 100% rational.