We are all aware of deceiving gradients, like "The Electric Brae" on the west coast of Scotland (A719 near Culzean Bay), but there are many other examples we probably all pass every day. They are just much more subtle.
One example I pass on a regular basis, is a hollow where, when it rains, the water gathers not in the perceived "bottom" of the hollow, but on the up-slope. Another example is on the A720 Edinburgh City Bypass. As you climb the hill, southbound/eastbound towards the Dreghorn junction, the car starts to pick up speed before the summit. And if you dip the clutch it still continues to pick up speed! I can think of many other examples of flat sections that are actually downhill, downhill sections that are flat, and the like. I am sure you can think of some near you.
