Keep calm and don't carry on when parenting teens. In a new study, psychologists find that mothers and fathers who are less capable of dampening down their anger are more likely to resort to harsh discipline aimed at their teens, and that fathers in particular were not as good at considering alternative explanations for their teens' behavior. Source 6d.
Can't go wrong with staying calm in any situation. When you get all heated and angry you tend to say things that you regret and actions become more vengeful than ethical.