The first camp lives by the rules of Miss Manners and always supplies their please and thank yous, sometimes floating sorries even when things are not their fault-- say a brusque gentleman forces his way past in a crowd, these people offer a reflexive sorry and almost immediately want to pull it back lest all of their sorries suddenly seem so meaningless.
The second camp avoids pleasantries of any kind for their inherent falseness and pretense to a kind civilization, the evidence of which is long outstanding. People of the scond camp blast through crowds and force sorries from people in the first camp and never offer anything in reply, but life is either meaningless or its meaning is measured in the number of excuse mes uttered and so those words must but guarded at all costs and given up only on the death bed or delivered with such hostility that words amount to a fuck you.
The third camp rests somewhere in the middle and is normally made up of people raised in the first Miss Manners camp who are affecting some kind of life worn ambivalence. They may say the occasional bless you when someone sneezes, but only as a base reflex they are trying to train their bodies away from.
I have oscillated between the first and second camp more or less. These days I feel a little bit closer to the first camp. The result being that I will frequently polish all of my interactions with some basic mundane pleasantry, the object of which can either take or leave. There are moments however where whatever small energy was placed in the kindness is taken, pulled inside out and blown back in my face with a terseness normally attributed to evil-hearted bureaucrats.
I have found that, depending on the neighborhood I am in, these moments can be countered. Though I seldom will give the satisfaction of entering into a full verbal throw-down with the culprit I will walk away and direct one of two basic mantras at the douche: "You should really be more aggressive, otherwise you'll never get what you want." or "You should really try to be more snotty, otherwise everyone is going to think you're dumb." Psychic sarcasm is the most withering form of the stuff.