I am one who does get involved if necessary, but sadly owing to my brain damage do not have the same perspective as other people so have to be really careful about this, though I must say 95% of the time the aggrieved party doesn't want to know, even down to cars being hit by others who drive off, happened twice now a few hundred pounds worth of damage each time, can't figure them out myself, though one accident I was witness to hid behind me when man got stroppy as I said I thought it his fault, she worked as waitress in local hotel and paid for a meal there for myself and another, which was nice.
Last year I stopped on the hill/road just going out of where I live as there was a broken down mini(old sort) coloured british racing green/dark green on hill with no street lights, flat battery so no car lights, "red light had been on over 60 miles"!!, I put 4 ways on etc behind him pushed him into nearby layby to safety he was a student and nearly at destination where relatives were coming from to rescue him, I carry two electric road flares in each of my cars for these times.
It would be nice if we were all helpful and nicer to each other, but not the way it is sadly