I've unfortunately met a good number of people over the years to whom the 'Cleese manual' applies, and they really are a poison on the rest of us. But what's always most amazing is how hilarious and ridiculous their strutting seems until it's directed at you - at which point it becomes rather scary. If they're so hellbent on shouting you down, especially if they don't know you very well, what else can they become hellbent on doing? All pleas for rationality are met with still more sputtering levels of irrationality until you realize that force and intimidation are they only language these people understand. The only thing one can do is appease them until it's no longer possible, at which point you have to show them the door and keep it firmly shut. A dirty business, but an unavoidable one.