Persian People

In the Rubaiyat are more reserved and take things in. They don't live in the moment. They're the people who like to stop and smell the roses.
"Whether at Naishapur or Babylon,
Whether the Cup with sweet r bitter run,
  The Wine of Life keeps oozing drop by drop,
The leaves of Life keep falling one by one.
In the Gulistan, they more outgoing. These people lived everyday like it was going to be their last day alive on earth.

The Flood

I think that te story was passed down from Gilgamesh's time to the bibe time. The bible just most likely tweaked the story  due to how they knew it. Most stories that get passed downchange a little bit. It's like the game of telaphone.