Suzzie - EXACTLY! That is why internal anger is the secret poison.
We don't know "what is wrong" but we do know "something" is wrong.
We have often been told/shown our whole lives that it is "wrong" to be angry.

"Oh you should just forgive. They didn't mean anything by it."
or even saying like this one my mom told me all the time: "Boys will be boys!" ((The implication is "You are wrong to be mad because this is something natural that just happens. You should just be prepared for it and expect it. There is nothing you can do or SHOULD do about this."

URRRR!!!!

All of that causes us to stuff away the issue and bury it deep inside of our mind. The result is a festering mess of anger that starts to stink but we don't have a clue as to where the stink is comming from!