Never try to discuss things with Physicists. (I distinguish between Physicists (Capital P) and physicists. The latter being somebody who studied physics but survived somewhat being a normal person, the former a absent-minded creature, only knowing other physicists, social life consisting of meetings and getting drunk with two other physicists. You get the Idea...)

Discussions with Physicists go around in circles, they always try to take EVERYTHING(TM) into account, they make up problems, they have no clue about what is realistic and what not. And for some reason they sometimes fall silent for about 30 seconds, staring around, and then start the discussion again. Maybe it is because they do not meet a lot of people, so if they have got the opportunity to talk to somebody, they overuse it...