Discipline is a system of teaching your child how to function within the family and society.  Modeling, or showing how do behave in certain situations, is one way of doing that.  Correcting a child in a heat of anger has two fallbacks.  First, you send a message that you disapprove of the behavior.  Second, anger can be blind, and you may act as if you were angry at the child while in fact you are angry at the behavior.  Third, anger may push you into making a decision to punish your child that you might regret.

The best correction/punishment after our children engage in undesirable behaviors is done when we are rational and unaffected by negative emotions.  it is O.K. to say: "I am angry that you...  I have to think about the consequences you deserve." to avoid rush decisions.

Best regards.