I've been in several discussions on MR where it has become apparent to me that we posters have our own opinion and are NEVER going to change that opinion (particularly when it comes to those things we hold dear, like our nationality, religious beliefs, etc.). And that's okay. It's what makes the world an interesting place to live. Presenting an opinion in a debate like format with information supporting a particular viewpoint helps people see all sides of an issue. Even though the debate may not ultimately affect any one's viewpoints, it can enhance them.
There are times when I've read some one's post and thought to myself, "What a dunderhead!!"(of course, I would never say that out loud

) because that poster's views were radically opposite from mine. However, I completely respect their right to hold and speak their views. Just because those views are different from mine, I understand that it doesn't actually make them a "dunderhead" nor does it make them less intelligent than I am. It's the times when my views have been held in such contempt and incivility by other posters and when my intelligence has been brought in to question which have tainted the discussion for me. I might attempt to clarify my point of view, but once it's apparent that the opposing view point has taken a negative turn, I unsubscribe from the thread and leave the others to it.
I personally think that the people who are so quick to become that negative do it because, thanks to the anonymity of the Internet, they can.
The posters here at MR tend to be more considerate than posters in the forums my 20ish children frequent. My 23 year old daughter occasionally asks me if I've gotten "flamed" yet and I am proud to say that it has not happened in the almost 16 months I've been a member here. (Actually, I think she's a little disappointed in me.

) I attribute this to the thoughtfulness and caring of the MR community. If we occasionally digress into vitriol, that happens in even the closest of families. I see that as an anomaly and not the norm.
Kudos, MR members and mods.