I think I am stupid, too. At work, to my consternation, quite often I do something only to realize how stupid that thing was. But, that said, I think knowing that we are not smart, is itself a sign of intelligence. Because introspection, or gathering feedback from the expressions of others, or thinking about somoething to realize we did it the wrong way, needs some intelligence. Agreed that we are not smart as many folks out there (like 70% of the people I work with), but I see many people who are too stupid to realize they are stupid. And one of them became our president recently. So, it's not quite as bad as we think it is.