Psychologists and therapists claim that narcissists hate boundaries. when you don't allow a narcissist to cross a boundary you've set, how are they affected by this? is this a narcissist injury to them? do they feel bound?? a lack of control?

Even when one has a personality disorder, we can only guess their feelings. The only way to know is to find out through direct communication (not all persons with the same personality disorder will have the same feelings in a specific situation). One should never allow anybody to cross one's boundaries, narcissist or not. And one should be grateful boundaries are respected.