Disagreeing with each other over the child's upbringing can create a confusing situation for the child. To avoid this type of situation, disagreements are best resolved when children are absent. Inconsistency between parents causes children to play one parent against the other. When parents disagree, children quite naturally go by the easiest set of regulations. It is easier for all when parents decide on a common set of rules.
Children learn values and beliefs more by examples adults set than by verbal instructions.
Screaming at a child to be more quiet or paddling a child for hitting someone who is smaller is not effective. Decide what is important and what parental response reinforces what you are attempting to teach. Frequently the message a parent sends is not the message the child receives. The words told one thing while nonverbal cues suggested the opposite. Mixed, or double messages leave a child confused as to which message should be acted upon.