And do not grieve the Holy Spirit of God, by whom you were sealed for the day of redemption. Let all bitterness and wrath and anger and clamor and slander be put away from you, along with all malice. And be kind to one another, tender-hearted, forgiving each other, just as God in Christ also has forgiven you. Notice the contrast here between conditions of anger and the results of impersonal love. Anger is a violation of the Christian's code of conduct as a member of the Body of Christ.
Anger hinders effective prayer.
Anger is always accompanied by other sins. Anger promotes the sins of gossip, self-righteous judging, maligning, revenge, complaining, bitterness, and many others. Lack of growth means lack of joy, lack of love, lack of divine viewpoint. Anger promotes jealousy and cruelty. Anger causes misery for loved ones, friends, and community.