That's assuming that your friends' behaviour is rational. For example, during the debate, while I certainly held my ground confidently, I didn't raise my voice,

That's assuming that your friends' behaviour is rational. For example, during the debate, while I certainly held my ground confidently, I didn't raise my voice, swear, engage in ad-hominem, belittle my opponent, or anything else that I would consider rude. What I did do is counter every statement he made that I considered false, which was quite a few statements. Clearly this riled him. But is it me who is to blame, or is it him for getting emotional about the fact that he is in the wrong? I have been a great many arguments where I have found, eventually, that I am wrong. I can't provide any evidence, obviously, but I can assure you that I am gracious in defeat. I simply say: "oh, that's interesting." Or "huh, I didn't know that, maybe I'll have to think about it again". But again, I think that comes from a) being quite confident that I'm not stupid, so that I don't have anything to prove to anyone, and b) being a scientist and thus having had these types of arguments with, shall we say, the creme-de-la-creme of smart-ass debaters ;)