This is a relevant phenomenon:
Having high self esteem is not a measure of ability. Likewise people making silly judgments are also likely less able to realise this. So it seems that being ignorant can be associated with increased happiness.
I am sure we have all seen people who are loud and confident (ie vulgar), have lots of children and are feckless and shameless. Statistically, intelligent people have less children to no children.
"Fools rush in where angels fear to tread." Alexander Pope