@metaphor- might be true, that is why there is democracy and free speech. With that, people will accept more coercion from government, because they can discuss to change things, rather then resort to violence.
Religion is a big one, and in my view often an irrational one. One more based on what people really want is based on the left-right discussion between individualism and community, but i might be wrong, there might be more.
Also, people do not affect each other directly on all levels, which also helps keep the peace.
@rocknrolf77 I agree, greed is a problem.