We don't know why, it just is. Cain brings a sacrifice, and it is not accepted. We don't know why, but it just isn't. Cain gets angry and kills his brother. It is misplaced anger.
Road rage is another example of misplaced anger.
Something happens in one part of a person's life, and then they get in their car, and you happen to be the unfortunate person who cuts them off. The anger comes out at you. Domestic violence is often misplaced anger. Something happens in another arena of life, and we come home, and we act out the anger. Any abuse, be it physical, verbal, or emotional, is always inappropriate.