Indeed. People have a hard time knowing when they are going outside their areas of expertise and sometimes extrapolate their confidence in one area into others

Indeed. People have a hard time knowing when they are going outside their areas of expertise and sometimes extrapolate their confidence in one area into others and can sometimes be right and other times wildly wrong. Diet and exercise might be one such topic, for example. Economics another. I'm not hammering speculation or suggestions, I'm specially referring to confident assertions.