The key to being a good parent is consistency. Yelling over time, too much  can lead to you as a  parent being tuned out. Your child may start yelling at peers with little provocation. Everyone yells. The point is to watch your voice and tone so that you maximize your effectiveness as a parent, and decrease your yelling quota so your kids won't write you off. The CNN psychologist Jeff Gardere stated we now know spanking is not good for children, it is related to a low IQ in children who are consistently spanked. These children never have their reasoning skills developed, like others. Their parents never explain life and the rules to them.
You need to do that, rules and the "how to of life" is your job as a parent -you teach this to your child everyday - by how you act,what you say, how you dress and the way you spend your time. Choose carefully. Remember, you can always change.