...when you're attempting to do something perfectly normal (fill in paperwork, complete GENDEC's etc) and an 'official' stops you with some utterly bizarre reason why you can't do it, despite it having been done for the last 50 flights or so, AND they are the ones requiring it. His explanation of why you can't do it is either a) physically impossible b) has the logic used by five year olds, or c) he simply repeats the original statement that 'No, you can't do it', as many times as it take no matter what sane and rational arguments you put forward.