Anger is a normal, often understandable human emotion. Yet, it is not an attitude that is always pleasing to God.

So then, my beloved brethren, let every man be swift to hear, slow to speak, slow to wrath; for the wrath of man does not produce the righteousness of God. (James 1:19-20)

A soft word turns away wrath, but a harsh word stirs up anger. (Proverbs 15:1)

Beloved, do not avenge yourselves, but rather give place to wrath; for it is written, "Vengeance is Mine, I will repay." says the Lord. (Romans 12:19)

Do not hasten in your spirit to be angry, for anger rests in the bosom of fools. (Ecclesiastics 7:9)