Illusion of explanatory depth (IOED): we believe we understand more about the world than we actually do.
Having a curious person (usually a child) asking us questions can make us realize how little we know about the world, even what we think we know pretty well.
There are too many things that I thought I knew, but probably I don't: interest rates, driving cars, faucets, venture capital, how to pronounce the word "error", how raccoon walks, and how to use etc in a sentence, etc. The phenomenon that we tend to believe we understand things better than we actually do is called the illusion of explanatory depth (IOED). We often fail to realize our limited understanding of things until we are asked to explain them. We only know what we know, and we don't know what we don't know.
This illusion is also related to the famous Dunning–Kruger effect, where it's about ability, while IOED is about explanatory knowledge. It is also important to note that the Dunning–Kruger effect might not be accurate.