wrote "But there must be people who don't feel intelligent enough - much as I don't feel athletic enough, or healthy enough. Right? Or does *everyone* think they're intelligent enough? "
People don't think they lack intelligence. They might say "I'm bad at math, or physics." But they think they have other powers, and they have access to privileged information (favorite conspiracy theory). They have a "gut feeling" about some people (politicians, billionaires, celebrities) that overrides common sense. When confronted with logical arguments, they often dismissively say "You and your logic..."