It means you've gone into the ego and you're experiencing false perceptions, through a very warped state of mind. Yes, when you're nuts, it can seem like you are totally sane, that you're totally right, that you're totally justified, that it's totally obvious why everyone else is wrong, and you can really really believe that you're doing the right thing (that you're the innocent one) by being offended by them.
Anyone who is not at perfect peace is experiencing insanity of some kind.
That's why it can be a difficult trap to get out of, because you don't recognize, or aren't willing to admit, that just because you're really sure that it's all someone else's fault, it's actually not.
Typically, any time that you become upset with someone or you have an outburst or get angry about what they're doing, it's usually because you were already feeling upset about something beforehand. Something was becoming exposed in your mind, coming up for healing, and someone pushed the button. They seemed to trigger you.
The part where you become so confused is that when someone else provides the trigger to ignite a fire inside you, you think that the only reason the fire is there is because they caused it. That's never true. The only reason the fire is there is because it was already there, and they just pointed it out. So now you're attacking the messenger because you yourself did not notice where the fire was coming from. They maybe even needed to come along and point out (trigger) your fire, to show you that you are burning up inside, because you were not aware of this. And in this way they are helping you.
You need to become aware of your shit so that you can open up to correction and healing. And usually we hire other people to come along and point out our shit so that we will become aware of what we're trying to deny. But we're in such denial that we end up projecting and blaming the cause of the upset onto other people, thinking they had the power to create it. We don't want to admit that we chose and caused it in ourselves or that we need to heal it within ourselves. The problem is within, not without.
So, pretty much guaranteed, when you're getting wound up about something and are slipping into that 'they are wrong' mode, in which clearly and obviously it really does seem like they're wrong - like its a no brainer right?.. that means you're mind is fucked up, and you're unconscious and insane. You're thinking that the cause of your problems is not yourself, which is not true, and are hallucinating that someone else is at fault for something they are not really doing. To go blaming someone for something they aren't the cause of is insane.
So we need to come back to sanity, and the first step in doing that is recognizing that even though we believe strongly that we're not mistaken, we are mistaken. We need to open up to taking full responsibility for being the cause of everything we're experiencing - its all coming from within ourselves, and we must have chosen it. We are doing it to ourselves, and nobody else is even involved. Even if we became upset "because of someone else", it's more like THANKS to someone else we've been shown how upset we already were, and now we need to go within and do some healing with Holy Spirit to undo this self-attack.