Since Goda was all in love with Noah and all, you should know a little bit about the generations of Noah and what it was like back then. Noah was the only righteous and blameless man of his time. Sure, he got bare-ass naked and piss-face drunk every now and then, but Jesus Christ, the rest of humanity was a shit fest compared to this good man.
You see, Noah walked with God, which of course is holy-speak for saying Noah was really, really close to God. At least when he wasn't passed out cold, drunk, and naked.
Now Noah had rolled his fat ass over on top of his wife three times and somehow managed to begat himself three sons: Shem, Ham, and Japheth. They're not important right now, but whatever. You've been told.
So the earth was corrupt in God'sb sight, and filled with violence. And God saw that the earth was corrupt in his sight, filled with violence, blah blah blah, and that all flesh had corrupted their way over all the earth.
And God said to Noah, "Noah, all human flesh has made the earth a very violent place, and I fucking hate violence, so I'm going to kill every living thing. There was a time when I really thought my creation was good. Well, I'm fucking taking that back as of right fucking now. I'm gonna destroy the whole fucking, ungrateful, violent earth."
And Noah thought to himself, "Holy shit, I need a drink."
a. Or, Yahweh.
b. Or, Elohim. Seriously. We changed Gods. Just fix it in post.