We can’t unconditionally trust the motives of people we don’t know, so we project a heightened sense of security upon those we do, even if common sense suggests we should do the opposite. If 90 percent of life is inscrutable, we need to embrace the 10 percent that seems forthright, lest we feel like life is a cruel, unmanageable joke. This is the root of naïve realism. It’s not so much an intellectual failing as an emotional sanctuary from existential despair.