Anger...>?

Psalm 78; Jeremiah 10:23-24; Nahum 1:2-4
  Ephesians 4:25-27,  Therefore each of you must put off falsehood and speak truthfully to your neighbor, for we are all members of one body.   “In your anger do not sin”^[a]: Do not let the sun go down while you are still angry, and do not give the devil a foothold.

After reading that scripture it seems as though God is recognizing that there will be times when we are angry but that we should not REACT out of that anger and therefore do ourselves and others harm. We need to RESPOND instead out of love instead. Which means forgiveness and reconciliation.

Psalm 86: 15, But you, Lord, are a compassionate and gracious God, slow to anger, abounding in love and faithfulness. 

God himself is slow to anger.... I think this means thinking before you let anger take hold and maybe even recognizing the consequences that could take place if you do react in anger. There are times when God gets angry, so anger in itself is not a sin, it is what we do with our anger that can lead to sin. God's anger is different and since we are more likely to sin out of anger, we need to be careful. So when anger takes hold in a situation, when someone does something that you know is wrong and you justify that anger, be careful what you do or say. Ask God for the right words, or even rather if you should speak at all.

James 1:19-21, My dear brothers and sisters, take note of this: Everyone should be quick to listen, slow to speak and slow to become angry, because human anger does not produce the righteousness that God desires. Therefore, get rid of all moral filth and the evil that is so prevalent and humbly accept the word planted in you, which can save you.

 So,  is it  better to forgive the person and leave them to God, If we know that God is a just God?
2 Thessalonians 1:5-7, All this is evidence that God’s judgment is right, and as a result you will be counted worthy of the kingdom of God, for which you are suffering. God is just: He will pay back trouble to those who trouble you    and give relief to you who are troubled, and to us as well. This will happen when the Lord Jesus is revealed from heaven in blazing fire with his powerful angels.