Maybe my choice of words was bad. I agree with what LinearAg said about possible reasons for the flood story:
Consequences of ignoring or sinning against God? The reason we have rainbows? Fitting of a legend from the past into their religious context?
You believing that the flood happened still begs the question as to how are we supposed to know when the bible is refering to an actual event, a parable, or a just-so story? Just because you believe the flood happened gives no-one else any basis to believe it leterally.