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.
Not sure if you'll be back to see this, but... how does this approach to comments align with the ideal of intellectual curiosity that HN is supposed to foster?
Although HN comments can often be — if I may put it metaphorically — hit and run, like a graffiti wall, is that the ideal?
Maybe it is the ideal, and I'm missing the point. :-)
People like to pretend that prolonged back-and-forth discussions are valuable. But at least in my experience most people, especially me, only have one or two points to bring to the table. After that the discussion quickly devolves into nitpicking or bickering.