A very common thing I see is smart people with low self-confidence/self-esteem. They have a belief that they're not good enough to "make it" or that they're not

A very common thing I see is smart people with low self-confidence/self-esteem. They have a belief that they're not good enough to "make it" or that they're not deserving. They will of course not get rich, because they never really try. Conversely I see not-so-smart people who do make it, because they're confident and believe they'll make it. I think success is much more dependent on mentality than smarts, but people focus on smarts because it is somewhat quantifiable.