You are right on the money with this post ... I have a set of principles on my website I call "The Rules of Polite Discourse" and they fit right in with what you wrote:

http://www.sosayssunny.com/polite.html  

My prior roommate and I compiled the list of commonsense rules and I composed the text.  The impetus was because she came from a family who fought bitterly:  She would come back to college after a visit home, crying, and had scars of a childhood divorce.  

I formatted it really nicely, printed it on ledger size paper (11"x17"), and burnished the edges with a lighter to make it look like an anchient document.  We adopted it as our family charter and were roommates for 5 years after college.  I can't say we didn't fight -- but when we did fight unfairly, the other one would point to the Rules on the fridge and we would try harder to respect one another.

The verse at the top, regardless of your religion or spirituality, is a good one:

"Do not let any unwholesome talk come out of your mouths, but only what is helpful for building others up according to their needs, that it may benefit those who listen."     -- Ephesians 4:29 NIV

Hope you enjoy!