I think you nailed it.

I do try to explain more in depth (too much). I'm working a lot on this and stop explaining when the main basis is covered, but my pragmatic approach forces me to cover ALL the parts.

I also agree with @WheelsAtLarge about that I might now know a subject as good as I think. When I start explaining something, I realize that I came short on explaining some parts because I lack the knowledge.

Thank you for your comment, it was helpful.