God - Evil, or just Stupid?
Either God is incredibly evil, or incompetent. Either way, why should people worship it?
Lets assume that God is omnipotent. He has the power to do anything, and created the world as he saw fit.
If I were to adopt some children, and then break a few of their arms, kill a few of them, and let the rest beat the living crap out of each other, then I'd be (rightly) accused of being an evil bastard.
Now look around you. If a god created this world with full knowledge of his consequences, then he is the most evil being. Hitler only killed a few million people - that's nothing compared to the horrors that god dishes up in the way of plagues and natural disasters.
So if you believe in a benevolent god, accept that he's a bit thick, a bit incompetent.
I personally prefer to believe that there isn't an evil or pathetic architect up there somewhere. The world is a self perpetuating entity, and we are lucky enough to spend a few brief decades in an amazingly tiny portion of it.
Thanks to natural selection we have highly developed brains, and that give us the power to mitigate most of the horrors that we see around us.
The Great Flood
You may argue that your god is giving us free reign to be good or evil. Natural disasters aren't his direct doing. That's fair.
But let's go back to the comparison with Hitler. Who is more evil. Hitler is responsible for the genocide of a few million people. The god of the old testament is responsible for the genocide of the entire world's population, bar a couple on a boat.
The Great Flood (according to the myth) is his direct action, and intent.
I have no idea why Christians teach their children about Noah. That storey paints God as the most evil entity in existence. No human has come close to being that evil. It is in direct contradiction to other teachings of God, who apparently, is all loving. Deny the old testament, or own accept the label of hypocrite.