I try to be respectful when disagreeing, clear what I mean when I'm teasing a poster in a friendly way, and when someone says something I don't like say something but give them the benefit of the doubt that they just had a bad day. My success rate at doing this is good but not 100%. I find that the regular posters here have been great about owning their crap when they mess up. Just the other day a regular poster got a little testy with an answer and totally got it and fessed up and apologized when called out.
This is my experience. We can all be dickish at times, but most everyone here will own up to it and apologize.