Anger may be harmful or it may be beneficial; it all depends on how you use it. Anger is harmful when it is inappropriate, unjustified, or uncontrolled. Anger is beneficial when it makes you get off your ass and do something and it prepares your mind and body for what they have to do.
Getting angry at inappropriate times serves no useful purpose, such as getting angry with an unruly child in a public place. Unjustified anger is always bad, such as getting angry when the baby will not stop crying. Uncontrolled anger usually leads to medical problems (stress) to you and others, or to injuries to you or others. It may also lead to legal problems, social problems, and lawsuits.
Justified, controlled anger used at appropriate times is a useful survival tool that nature has provided us. Do not reject anger as a fault, instead, understand it, and use it.