I find the anger, tension, and rudeness mostly begins to cultivate when something is misinterpreted. People take and may say comments in the wrong way or respond to them in an unkind manner. People often feel, I've noticed, that it is an invitation to be rude back, when no such invitation was sent. (And when it is, the one who sent it wanted you to respond in a rude or impulsive manner. :c)
I feel we sometimes fail to heed the words of Henri Amiel when he said "There is only one way of not hating those who do us wrong, and that is by doing them good". And while some do wish to bare this hate, one must realize hate is a complete waste. It is one of the few things in this world that do waste one's time here. Hate destroys, and in the end hurts the one who attempted to us it in the first place.