To test whether you really know something, try to explain it to someone with no knowledge of the process at all. If you can explain it to a 6th grader, you’ve got it down.
Some people pride themselves on the ability to explain things to other experts and do not care to explain it to anyone else. They believe that the details are best left out. Why bother simplifying something that everyone else already understands?
Here’s the thing, people who think they understand things often have fundamental knowledge gaps. This gap may not actually be a problem day-to-day. The person likely doesn’t come to a situation where it matters. However, if their explanation is built around fitting this gap in, there may be trickle-down issues.
Take finance systems as an example. Almost no one understands how Wall Street works. Do you really understand what makes a stock price go up or down? How many people does it take to make it happen? What impact do shorts and longs have on the price? To most people, simply understanding that “the Market” dictates the price is enough. But if you were asked to model it, you better know how “the Market” actually works.
Describing a process in plain language forces you to confront the details. “The Market” is not plain language, it is shorthand for a very complicated series of activities. A process built around “The Market” can very easily be shown to be incomplete.
I come across issues all the time caused by experts who think they understand something but actually have a very fundamental gap in their knowledge. Never assume that experts actually get everything, that’s one of those process gaps.