To explain and to have the knowledge, is different.
Explanation is hard, and its a constant learning process, I will definitely say yes to that, I an not good at explaining things in the best ways to others. Then I decided to study my attitude during explanation and the behavior of my brain when people ask me to explain things. Oh yes!, the best thing to study life is via oneself, that is an opinion, however, when you understand who you are, what you can do and where you want to head to , you can become more focus than usual.
Back to the topic, I found out recently when I try to explain how things works, right back in my brain, some part of it questions and under-estimates the ability of the other person to understands me. During that I end up complicating my explanations in the processing of trying to make it more simpler for the person to understand.
To be sincere, I've find this behavior in other people when they try their best to explain to others and end up complicating things up. I think we put too much effort sometimes trying to explain things to others people, instead of going straight to the point and elaborate on points base on the questions are asked . This give more room for the learner to ask questions anyway ,for their own understand in other to organised this knowledge. Just like every processors are micro-architecture differently , humans brain are not different.
This behavior or attitude can be involuntarily sometimes and later can developed into an attitude, of-course, we are made differently and one brain handle things differently too.
You might have the knowledge , but the ability to pass it to others is by far the hardest. Explanation is not a gift , it can be learned. The best teacher is life and as you grow older, you learn and learn from it. To be good in explaining things one have to be a good listener, to be a good listener is to be curious to learn. I've listen to good presenters and I admire what they have while others struggle in that.
Finally , explanation is a skill set and it requires time,patient and good knowledge of the subject in question.
To understand, is to learn , to learn is to ask questions, and to ask questions is to be encourage and bond.
The more you thinks you know the less you know.