"Personality disorder" is in many ways just a way of classifying and identifying particular common types of exceptionally shitty people. However, it is also a matter of a completely different orientation toward the world. The difference between being average-shitty and personality disorder-shitty is a matter of intransigence and dusconnect. Narcs, for example, rarely stop behaving like narcs, because - specifically due to their disordered personal/ world view - they dgaf that they wreak havoc and ruin lives as a matter of course; all is warranted bc it gets them their strokes - and the strokes are the Alpha and the omega, which is not like normal people. If you don't have the normal ability to recognize other people as human and behave accordingly, if absolutely nothing (not even your own children) matters enough for you to put them before your own interests EVER, if you you know you are a destroyer and truly do not care but do care about twisting the world to you, then you are beyond merely "shitty." Lots of people behave in shitty ways from time to time without having a "disorder." Those people may adapt situationally, or reach a point where they stop acting like a shit. But if you've ever truly talked to (again for example) a narcissist, they do not have a normal orientation towards others/humanity in general. It's not just, "yeah, that's shitty but I don't care"; it's "I don't know what that [normal consideration] means and more importantly how can I dispatch you because you're just something I need to get out of my way." It's a whole other level of shitty.