davidovitch should not be replying in such a manner. If some one is not understanding your point, then one must find fault in himself. That you are not communicating effectively. I may understand a point but it does not mean i can effectively communicate to make the other party understand. When ever responding to people always keep their perspective in view, ie where they coming form. What we do is we just make our point, and if someone objects or disagrees we shoot him down. Whenever someone objects or disagrees with one's viewpoint, immediately review your position in light of the objection or disagreement.