I expect that I have been on both sides of this "problem" as I've tried to climb the learning curve. The real problem (IMHO) is that we seem to expect a greater ability in mind reading that many or most folks have. Some people are very perceptive and sensitive to non- verbal cues, and others far less so. "Ettiquette", just like music, is a thing that has to be taught AND learned. Courtesy and common sense go a long way, but, sometimes, you just have to vote with your feet.