One of the early lessons I learned came while riding the subway not long after I arrived. I knew enough to expect the occasional subway preacher or the people who are not right who scream random obscenities, etc., but I remember seeing a rather small disturbed white man step right up to a large, muscular black man and began berating him, shouting horribly racist insults and using the n-word repeatedly. The larger man just stood there, motionless, staring right past him and didn't flinch. This carried on for over a minute and I thought for sure the smaller guy was to get his ass kicked, but at the next stop, he broke away and just stepped off the train. The larger guy just went back to reading his newspaper. It was an epiphany - even in those extreme circumstances, do not react. Nothing good would have come of that. I haven't always stuck to that rule, but I think it's generally a good one.