While I have never been banned, I have been warned several times by dang about my behavior and I deserved every one of them. It seems to have worked too, because a lot of times I'll write a nasty comment and there will be this little voice in my head asking "what's dang going to think of this?" and I'll either edit it, not post it, or delete it.
When I feel a bit to much about a subject I open notepad and write the comment there and then just close the window if it feels inappropriate. This way there is no risk that I accidentally post it but it still feels like I got to say what I wanted to say. And then I can write something more levelheaded.
There's also the 'delay' setting that you can set in your HN user profile, which gives you 1-10 minutes to edit your comment before it becomes visible to others. This has saved my bacon on many occasions.
