It would be nice to say the rich people, the fancy people, all behaved like bastards and the poor slobs all came through like heroes. But as a matter of fact, sometimes the poor slobs behave like slobs and the great, noble, privileged characters come off very well, indeed.
I look for something that is highly unusual, involving ordinary people caught in extraordinary situations.
Someone once told me the one thread that runs through them all is a premium on personal courage - not intellectual courage, but just plain physical courage.