"We often make the fatal mistake of thinking growth opportunities come to an end when something or someone becomes part of our daily routine. When things become familiar and predictable, we become mindless drones. We tune out. As soon as we think we understand something, we stop paying attention."
~ Todd Kashdan, Curious?: Discover the Missing Ingredient to a Fulfilling Life
This quote reminds me of a post Avoiding automaticity which I wrote some time ago. I agree with Todd that when it seems like you fully understand something this is always wrong. When you curiously explore that thing you'll find out there is always a great complexity beneath your current understanding which offers great opportunities to learn. This process of exploration is basically asking yourself some questions like: What do I precisely understand about the topic?, How could I explains this topic in simple terms? How does it work?, How do I know this?, How does this topic relate to other topics?, How can I understand how and why other people view this topic differently?