Look, a discussion usually works in the way that one side presents an argument, and the other side point out flaws in it. Over the course of the discussion, you end up with an end result with most obvious flaws ironed out, and you have stronger and more definite knowledge.
A discussion doesn't work in the way where you go "my argument is right, kthxbai" - I mean if you feel my argument is a "cheap way to counter your argument" (as if I cared who said what), why don't you elaborate and make me see my flaws, rather than sulk like a 5-year old?