[Antoninus]

My experience is useful intelligence peaks at the Master’s level.

Define "useful". In my experience, the people who live the best lives often don't even have a college degree.

[cgbg]

the people who live the best lives often don't even have a college degree.

They are much more likely to mind their own business rather than trying to tell other folks how to live their lives--exactly the kinds of folks you want for neighbors--and relatives!