This is one of the few sites that lets you say what you want to say and not think about it further. If I see something worthy of a response that might turn heated, I add my comment and don't return to the discussion. Other sites use notifications that force you to read responses to your comments.
Cuturally, for me, losing my cool is a sign that you've been beaten. I do my best to stay in control all the time - though there are inevitably times that what I'm trying to say doesn't translate into what I type.