There is not ONE area of life where I believe I have complete knowledge or expertise. The more I learn, the more ignorant I realize that I still am. I could study every day all day for the next 500 years (if I were immortal) and barely scratch the surface of what there is to know. Then there's the intelligence issue. Mine is average at best. Just because I read about something, watch videos, or take online courses doesn't mean I'll understand it or retain it. As with any human being, some topics are easier to understand than others. There's SO MUCH that just goes over my head. I'm OK with my limitations.