On reading Ken's post on rituals:
I've been thinking about this recently. I think a culture defines a set of public and private expectations of its members. People that do not conform to these expectations are cold-shouldered. We usually call it being rude, or antisocial. In one society, one finishes everything on the plate to show it was good. In another, we leave a little to show we the host was generous. There is probably a historic reason for each, and doing the wrong one will make us seem rude.
The key is that a culture needs to be largely predictable for it to function. I need to be able to expect to go to dinner without taking a plate, or to know to take my plate. The more uncertain the behaviour of everyone else, the more precautions and preparations I have to make.
In a village, social cohesion is important, and there are not that many people, so I can and should greet everyone I pass. But in a city, I cannot afford to greet everyone I pass, and the culture must permit this. So we have cities where no-one makes eye contact, despite inhabiting each other's personal space.
A different slant, however, is provided by the religious or moral code. Often, particularly for the believers, these are not merely rituals but ways to honour their diety; the ritual represents their own hierarchy. She chose to observe her ritual instead of socialising, which some will respect and others will see as an affront.