The Keli Yakar described the corruption of the generation of the Flood. They were guilty of three major sins. They practiced sexual immorality, idol worship, and theft.
Noach was praised for not allowing himself to be involved in any of these transgressions. When the Torah says that he was an איש צדיק, a righteous man, it implied that he did not steal. When the Torah says, תמים היה בדורותיו, that he was naive in his generation, it was an indication that he remained faithful to his wife. And when the Torah said, את האלוקים התהלך נח, that Noach walked with G-d, it was a proof that he did not worship false gods.
It is interesting to take note as to what happens when one abandons his belief in G-d. Since he no longer has accountability to a higher being, he can do what he wants.
He will not need to restrict himself in satisfying his physical urges. He will justify being in an adulterous relationship, because “it feels so right.”
He might need money, so what’s so bad about cheating, misleading, and stealing from someone. Everybody gets away with it, so why shouldn’t he?
He may be seduced into believing in some kind of blasphemous cult. He needs the love that they profess that they will give him. And they are always willing to feed him. Since his needs are being met, he need not examine the truth or lies of the cult.
We get a glimpse from the Torah how society can easily go bad, when they negate the greatness and power of the Al-mighty. It was true then, and sadly, it is true today as well.