It's really interesting how most personality disorders don't really express themselves unless in the face of some trigger. And identifying triggers is important to change behavior. 

I have one coworker who sometimes I suspect of being NPD or really overtly BPD (pretty sure I am quiet or covert BPD I guess) and I just think...ugh he's so rude and fake nice. Then sometimes he seems like a half decent person and actually funny and reasonable. 

I guess this is the "grey" area that everyone talks about. He just seems to suck when triggered in some way. Like anyone else with a personality disorder. 