This is still one of my favorite cartoons of all time (by S. Harris). I think we've all been there before, trying to waive our hands in place of providing a good reason for the procedures we use.
A closely related phenomenon is when you receive an explanation for a business process that is "proof by confusion", whereby the person explaining the process uses lots of buzz words and complex terminology in place of clarity, probably because the person him or herself doesn't really understand it him/herself.
This is why clarifying questions are so key. I remember a professor of mathematics of mine at Rensselaer Polytechnic Institute named David Isaacson who told a story of a graduate seminar. If you have ever experienced these seminars, there are two distinguishing features: the food, that goes quickly to those who arrive on time, and the game involved of the speaker trying to lose the graduate students during the lecture (an overstatement, but a frequently occurring outcome). Prof. Isaacson told us of a guy there who would ask dumb questions from the get-go: questions that we all knew the answer to and most folks thought were obvious. But as the lecture continued, this guy was the only one left asking questions, and of course was the only one who truly understood the lecture. What was happening is that he was constantly aligning what he thought he heard by asking for clarification. The rest of those in the room thought they understood, but in reality did not.
It reminds me to ask questions, even the dumb ones if it means forcing the one who is teaching or explaining to restate their point in different words, thus providing better opportunity for true communication.