[narf poit chez BOOM]

Personally I've found the Bible and the Book of Mormon very good at explaining societal behavor.

Society is in golden age,
Society starts crumbling as people forget about the principles that brought about the golden age,
Society falls apart into bloody violence,
People start building a new society on proven principles that, at the very least, include dedication,
Society is in golden age,

Rinse, repeat. That's the whole of history, from Rome to Assyria, from the aztec's to Canada, a society is built upon principles. Maybe not good principles, but the people beleive in them and work to make them work. Some of them, like the aztec's, would have crashed anyway, because their principle's were unsuportable (At the least, they would have run out people). Other's, like the romans, had good principles and bad principles - and their empire lasted, in one form or another, for a long time.