I suspect that flat-Earthers come in (at least) two varieties: The true wackaloons who are clinically nuts and living in a fantasy world, and who are a tiny minority; and the great majority who are just having fun with a mind game, don't really believe any of it, but get a kick out of making the rest of us pull our hair out in frustration as they invent answers to every objection. In high school I had a science teacher who challenged us to prove that we are not living on the inside of a hollow sphere that is shrinking at an accelerating rate to keep us clinging to the inner surface, and which is subjected to a peculiar geometry which makes it unthinkably far straight up overhead to the opposite inner surface, and very short straight down and out and curving around to the opposite surface. Nobody in the class could come up with a proof. At the age of 15 I could not do it, and I'm not sure I could today. The flat earth is something I could see that teacher proposing, to test the ability of his students to find the flaws in it.
FWIW, I'm reading Sourcery by Terry Prachett just at present. Prachett manages a very convincing explanation for Discworld. Something about God having more imagination than practical ability (?). I forget how he actually puts it.
With respect to memory: I can forget things in a matter of minutes, and then remember them the next day. And when learning a language, I know that constant repetition of vocabulary is essential, at least for me. I need to encounter a word in reading many times before it really sinks in.
And of course Mary Ann was far prettier than Ginger. I totally had the hots for Mary Ann. I'd have been 17 or 18 at the time.