Revenge might seem sweet but it is evil and offensive to God.
It is wickedness and ignorance that makes humans want to satisfy themselves by avenging offences.
Humans do not believe that God executes judgement and justice.
This is lack of faith in His word because the Bible clearly portrays God as a God of justice and judgement.
God will avenge and execute vengeance on people who harm others.
He is not weak. However, most people do not believe in the power and justice of God, that is why they make sure that those who hurt them pay to the last cent.
That is rendering evil for evil and it makes us guilty before God.
We must never render evil for evil.
See that no one renders evil for evil to anyone, but always pursue what is good (1 Thessalonians 5:15 NKJV)