How I envy you all who have not met legitimately stupid people. In no particular order, I've met, studied or worked with many of them, including but not limited to:
A woman who adamantly held that the moon landing was faked, her argument being that she'd never heard about anyone going to the moon since -69, thus it was just a publicity stunt. This in the face of a "list of people who have been to the moon since -69", which was fake too, of course.
A man who could not grasp that a "public school" is not a public place, and therefore his right of free speech does not extend to handing out racist propaganda at one.
A man with no drivers license (done the test 5 or 6 times, I forget), who owned 6 cars. The kind of cars that get sold cheaply to new drivers rather than being sold for scrap value because the owner wants to be nice. He bought these, because his equally stupid father insisted that it "was a good deal".
A man I took a hunting course together with was half-blind. This he neglected to mention until the firearms practice started...I should add, this man owns his own land, and intends to hunt on it. half blind!
Those are just off the top of my head. Stupidity abounds.