We often don’t know why we do the things we do, but we are quick to make up a reason we actually believe, even though its not true. Psychologists call this ‘Confabulation’.
The falsification of memory in which people fill gaps in recall with fabrications that they believe to be facts. Confabulation is, for example, associated with rational explanations, retrospectively given by people, to account for irrational behavior that has an unconscious emotional cause.