Kansas really is flatter than a pancake: http://www.improbable.com/airchives/paperair/volume9/v9i3/kansas.html
Yep. Oddly enough, the imperfections in the flatness are visible, sort of. Kansas has this thing called a "rise," which is a hill so flat you can't really see it as a hill. The way it works is, as you drive, you notice the horizon is actually creeping closer. This is startling, because you don't see a hill anywhere, but you realize the horizon is acting the way a hill would act if a hill were there. Eventually, you get to the "top" and your view broadens out again.
ROFL!! Thanks for post that. I also liked the link in the references to "Comparing Apples and Oranges".
We also tend to think of the Earth as a whole as being very "bumpy" -- an impression reinforced by topographical globes, which have their vertical component greatly exaggerated. But actually, if the Earth were the size of a billiard ball, it would be pretty much as smooth as a billiard ball as well. Even taking into account the extremes of the height of Mt. Everest and the depths of the Marianas Trench, an Earth shrunk to a three-inch diameter would have a surface smoothness perfect to within 2/1000th of an inch.