Even the righteous are not exempt from God's wrath when they anger him. Mistreatment of Others . False Prophets . There are many instances of it in the Bible, too. Cain, Esau, and Jonah are cases in point.
Unrighteous anger stems from evil human traits, including jealousy, carelessness, and selfishness.
There are also Biblical examples of people displaying righteous anger. They were all occurrences which also angered God. And this is the key to righteous anger. If it is something that does not also anger God, then it isn't righteous anger. On the other hand, if something angers God, then we can righteously be angry, too, so long as we do not sin in our anger.