There was a man named Andrew. He had done something terrible, something so bad that his mind refused to even acknowledge that he did it. Instead, he created an entire world. A new reality where he was a hero and he could solve a mystery that would save people. He didn't have to be a monster. That was his reality.

What makes his reality less valid than the one I perceived for him? It wasn't the truth, but it was his truth.

Point is, even if you're right, even if this whole thing is some sort of dream or illusion, the choices you make, the relationships you form, the things you do, are no less relevant here than they are in someone else's perception of reality.