Ebbie, it's simple - fear of consequences. If you're more afraid of the consequences than of your conscience, then you'll sit and do nothing.

This is somewhat enhanced, I think, by living in cities or other large communities. The "unwritten rules" for trains show clearly that for people in very restricted conditions, the only way to respond is for everyone to pretend that everyone else isn't there. And once you've constructed your shell, I think what happens outside it becomes less relevant to you.

Graham.