Have you ever heard of the #DunningKruger effect?
Generally, it is understood as
"a claim about general overconfidence of people with low intelligence" [wikipedia]
This actually isn't, what the original study said, but it is still what most people think, when they hear the term.
However, in my personal experience (anecdotal evidence) I find the most extreme levels of unfounded overconfidence about one's expertise concerning almost every aspect of life concentrated
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