To stay cooperative, take a break at the first whiff of anger or defensiveness.

Exit and Re-entry argument-prevention strategies are based on a simple reality.  Most people who know collaborative communication skills can succeed in using their skills effectively when they are emotionally in a normal zone--and then throw them out when the begin to get heated.  The more they feel frustrated, irritated or angry, the more likely that they will spit out dumb and hurtful comments.  

In other words, getting angry is to talking cooperatively what high speeds are to safe driving.  The odds of dangerous mistakes zoom upward as your angerometer begins to spike.