If God is so good why did He create Noah's flood?

why is it that God can be Good and Evil and still be considered totally good - while we if we get angry and such are moody at the least if not down right evil - isn't that hypocrisy in it's highest form - and Because He is God is not a good answer because we are His image as the Bible says : isn't it more HE is the highest angel and the lowest Demon - and to stay on HIS good side is almost always recommended - or is this already thought through