Great story!
I just wish more CC were as assertive as you at dealing with the less well socially educated individuals who grace the skies...!
I don't listen to the 737-300 briefing any more as I pretty much know it off by heart (unless its an unfamiliar airline) but I do respect the fact other people need to listen and I keep quiet during the safety briefing. I also count the number of rows to the exits infront and behind me - whether I'll remember it in a major emergency, I don't know, but its worth a go...I believe a number of crash survivors have attributed their escape to this simple task...