I branded myself Dumb ***. I may be able to fix a computer if it's ailing, but my knowledge of Windows is scarce and my knowledge of anything else is infinitesimal.
There are three types of knowledge: what you know, what you know you don't know, and what you don't know that you don't know. What I know compared to what I know I don't know and what I don't know that I don't know is equal to a cup of water to an ocean. I may know some, but pretty much nothing when it all boils down. I'm not even an "expert" in a single category, and there are thousands.