"Anger takes many forms, but it cannot long deceive those who will learn that love brings no guilt at all, and what brings guilt cannot be love and must be anger. All anger is nothing more than an attempt to make someone feel guilty, and this attempt is the only basis the ego accepts for special relationships. Guilt is the only need the ego has, and as long as you identify with it, guilt will remain attractive to you."
"Very simply, the attempt to make guilty is ALWAYS directed against God. For the ego would have you see Him, AND HIM ALONE, as guilty, leaving the Sonship OPEN to attack, and unprotected from it."
If you look, when you are angry or frustrated or even slightly annoyed with someone, while the feeling may be one of "anger", the process is really an attempt to make someone feel guilty, and the purpose is to displace your own guilt onto them. When you look at it as "trying to make them guilty", it's exactly that and only that.
Any attempt to point a finger of blame and say, "you are wrong" or "you did it" or "you shouldn't have done it" or "it was you" etc... is really an attempt to try to force the person to BE guilty, trying to cause guilt in them, trying to enforce guilt upon them and turn them INTO a guilty party. It's therefore a form of attack and a denial of free will.
When you get done being angry with someone you'll notice you were trying to make them guilty. You wanted them to be intensely identified as the sinner. You wanted to be right about this. And you wanted them to admit to their sinfulness. It's like a demand, and "love makes no demands."
What this shows you is that whenever we are angry, we are attacking, and are actively trying to hurt someone through guilt-inducing force. We are trying to convert them into the guilty party and are justifying it and backing it up with all our "reasons why" they actually are guilty.
So that means being angry at someone is not a neutral activity, or an unharmful activity, or a loving activity. It is actually an outright attack for purposes of displacing your own guilt onto another. "You but accuse your brother of your own sins."
In the anger it will always seem like you have amazingly justified reasons as to why you should be angry, because it's very clear why the person IS guilty. They DID seem to do something. They DID make a mistake. They DID hurt you. They DID move your cheese. They WERE abusive. They DID steal from you, or whatever. At least on the level of form.
This gives you a free pass of righteousness. This "righteous anger" is an excuse for making it okay to attack a person. The "justified outrage" passes for some kind of "right" that you have, because the occurrence is so obviously awful, inhumane, unjustified, un-asked for, vicious and the various other forms of what we'd identify as sinful based on appearances. But there is NO forgiveness in that view.
This means if we're not being forgiving we're not being loving, and you can't be loving or forgiving while you are being angry. This is because in the anger you are being unloving and unforgiving toward yourself, have accused yourself of sin and are now attempting to project that onto someone else, taking this wonderful opportunity they presented as a low-hanging fruit that you can easily attach your guilt to.
If someone does actually mess up, if they do attack, if they do something "wrong", this makes it extremely easy for your ego to pounce on them. Because now they've presented you with what seems to be an "actual sin". This makes it easy for you because you don't even have to invent a sin for them, they did it all by themselves. And now you can take this chance to push YOUR sin onto them by NOT forgiving them for theirs. It's a free pass.
There is no such thing as justification for anger. As ACIM says, "Anger is never justified". The justifications are lies, the appearance of sin happening is blindness and judgmental, the feeling of righteousness or deserving is completely unforgiving and a form of attack. Only by overlooking what your brother did can you be forgiving to him and to yourself.
"Forgiveness recognizes that what you thought your brother did has not OCCURRED."
"In this view are all your sins forgiven."