I just had a young woman in my taxi who received some dire news about a family member during the ride to the airport. She suddenly burst into tears and great, wracking sobs of emotional distress.
There are very few things that will put a man on high alert quicker than that. It's a hard-wired biological response; the CNS floods with adrenaline, vision and hearing get sharper, and the primitive lizard brain commands that the threat be found and killed. But, with nothing to fight, it turned a routine 30 minute drive into an ordeal of white knuckles and grinding teeth.
I don't put much stock in biological determinism, since we humans possess the ability to override most of our biological impulses, but it is very foolish to underestimate or disregard the profound and constant effect that biology has on our physiological, cognitive, and emotional processes.
I dropped her off about half an hour ago and I am just now starting to calm down. My nerves are shot, I'm exhausted, and I just want to eat and go to sleep.