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.
I look for something that is highly unusual, involving ordinary people caught in extraordinary situations.
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.
