But on Cain and his offering he did not look with favor. So Cain was very angry, and his face was downcast.
Genesis 4:5 (NIV)
It is ok to be angry. It's ok to be "VERY angry."
But the word here is a kindled fire. It is wrath that points to vengeance and destruction… only we are not wise enough to know how to apply it rightly, so it burns out of control.
This wrath is reserved for God, who is the only one who can wield it correctly.