When I went to school, an instructor explained that they quit teaching trouble-shooting, because some people can do it and some can't. I've learned that's true in other areas. Some people can't carry a stick of 4 inch rigid. Some can't bend conduit. Some can't wire a three-way switch. Some are afraid of heights. Some people can't get to work in time to get in the truck, some can't get to work some days, and some take drugs at work. I had one apprentice refuse to wear safety glasses. Not everyone is going to be an electrician.
That's got to be the best summary of personal limitations in the electrical trade I've read. It's exactly like that too, some guys stay in the trade forever and never figure out certain things.
