Indeed, for only a smart person can come up with a twisted and convoluted rationalization that a person with an IQ of 75 is not stupid and a person with an IQ of 125 is not smart. You'll find some of the most passionate arguments about the problems of IQ testing from people with IQs over 115. If you really think it doesn't matter, well, I'm sure there are some interesting ways to knock down your IQ quite a bit that y…
A very good old friend of mine is a professionally trained waiter and never had "advanced" math classes. His knowledge of math was limited to the rule of three.
One day I tried to teach him functions, quadratic equations, basic analysis and other stuff. He grocked it immediately. Much much faster than most of my class mates when we had to learn these topics back at school.
I think it is important to distinguish between "knowledge" and "intelligence".
A good life lesson was given to me by my English teacher in high school. He always told us that when you notice that you have more knowledge in area than the person you are talking to, then it is your job to adjust your way of communication. Not the other way round. It's of no good to be smug. In fact if you fail to communicate your ideas, you might not be as smart as you might think.