As you throw logs on the campfire, the perimeter of darkness grows.
I like that one. I've always thought of knowledge as a sphere and what the surface of the sphere touches is the intersect of your knowledge with what you know and don't know. As your knowledge grows so the does the sphere and your awareness about what you do not know.
Not saying that business people are less intelligent (far from it, good business people are as rare as good hackers). But pointing out that in the business world, confidence is a signaling mechanism for success when they speak to others outside the business field. This easily gives rise to an impedance mismatch between the business world and the technical worlds. Appropriately enough, the very best business people I know when talking about an issue their own field are just as doubtful about themselves as good technical people.
Fractal difficulty of a field is the impetus for a lot of this doubt, and it seems pretty opaque to outsiders in every field I've seen. This seems to be prevalent here when many hackers do not acknowledge the difficulty of marketing, sales, accounting, etc.
Also, the smarter you are the more you tend to doubt yourself. Whereas less intelligent people tend to have more confidence in what they're doing.
Bites me in the ass all the time.