What if the Earth was flat?

What if the earth was flat like a piece of paper. I guess that would mean we wouldnt have all the different climates and things like mountains and valleys and lakes. The ocean would be a big wave of water on one side of the planet, right? That means if you go far enough west you would reach the ocean. That would also mean that if you went far enough south you would reach the ocean. So what if you did both, you would reach the ocean. Which means that someone in Alaska could see the ocean on the horizon just by traveling west. What if the Earth was flat.