I disagree with Mr. Balko's comparision of feudal samurai with psychopathy. Granted I am no expert in samurai. I agree that both may share some characteristics such as lack of empathy/callousness--as in when testing the sharpness of one's sword on peasants, but I believe characteristics such as loyalty to one's lord, duty, budo as a purpose of life, and acceptance of responsibility would not be consistent with psychopathy. Also, my image of a samurai would not include characteristics such as pathological lying, conning/manipulativeness, early behavioral problems, or engaging in a wide range of various types of criminal activity. A samurai was an efficient instrument of his time.
My original reference to psychopathy in this post was to underscore that there are some individuals out there that for whatever reason may choose to focus their malevolence on you. Posturing in response to some such individuals could be a very bad decision unless one feels confident in a melee situation. One cannot easily make an assessment which persons those are.
I have been in a few situations outside of a work environment where most likely the other person would have come out rather high on the psychopathy scale. Where neither me or mine nor some other individual was the immediate focus, I moved to the periphery. In one emergency mental health situation where I was most certainly the focus, and the other man was bigger, drugged, and pulled a box cutter, (about five years before I began studying aikido), I can now see that I used verbal aikido to blend, deflect aggression, and take over the center. I then exited and contacted the police. Four of whom responded in an extremely professional and competent manner. Ultimately no one was seriously hurt.
I study aikido, not aikijutsu. Aikido has helped me with getting more out of my head, improved my balance and movement, self-confidence, and has increased my "spider sense" of potential dangers on my periphery. Mostly I would look to extricate myself from impending violence, but if I could not, I would not feel panicked. That's all I can say.