@boomerang,
In fact, if you point out that a person has psychopathic/sociopathic traits - it's taken as an insult...no matter that it may be true, and no matter that the person may be quite charming, socially adept, with great manners (ie a likeable person)
That to me say that most peoples understanding of it is - as drewdad pointed out, as being akin to a serial killer.