Some people simply don't have the intellectual capability or are just too lazy to look at themselves and others and analyze other people's behaviors and their own. I remember seeing partterns in people since my early teenage years and asking myself if they actually tried to mimic eachother and this was normal. Most of the girls during my highschool years left me feeling uncomfortable because I felt they were almost following some kind of "script" or something (buying same shoes/clothes, beeing nice to the better looking guy and mean to the others, sometimes contradicting themselves without caring at all) and that there was in general less variance between their personnalities than the boys.
When I later learned about eovlution and better understood the process of selection I could somewhat rationalize what I did not understand. Some of that included the fact that most people want to believe what makes them feel better, and think that the world functions according to their rules, as long as it somewhat works out and enough of their peers believe it as well. Religion for instance is just a "hardcore" version of that. Even a large part of the scientific community.
Requires a great deal of effort to constantly try to be as objective as possible. One could even say that it is inefficient from an evolutionary standpoint, especially for the female sex for which the role for hundreds of millenias has always been to raise children, not to understand the world to better extract its ressources / it's energy.