I am beginning to suspect that it is surprisingly common for intelligent, competent adults to somehow make it through the world for a few decades while missing some ordinary skill, like mailing a physical letter, folding a fitted sheet, depositing a check, or reading a bus schedule. Since these tasks are often presented atomically - or, worse, embedded implicitly into other instructions - and it is often possible to get around the need for them, this ignorance is not self-correcting. One can Google "how to deposit a check" and similar phrases, but the sorts of instructions that crop up are often misleading, rely on entangled and potentially similarly-deficient knowledge to be understandable, or are not so much instructions as they are tips and tricks and warnings for people who already know the basic procedure. Asking other people is more effective because they can respond to requests for clarification (and physically pointing at stuff is useful too), but embarrassing, since lacking these skills as an adult is stigmatized. (They are rarely even considered skills by people who have had them for a while.)
This seems like a bad situation. And - if I am correct and gaps like these are common - then it is something of a collective action problem to handle gap-filling without undue social drama. Supposedly, we're good at collective action problems, us rationalists, right? So I propose a thread for the purpose here, with the stipulation that all replies to gap announcements are to be constructive attempts at conveying the relevant procedural knowledge. No asking "how did you manage to be X years old without knowing that?" - if the gap-haver wishes to volunteer the information, that is fine, but asking is to be considered poor form.
(And yes, I have one. It's this: how in the world do people go about the supposedly atomic action of investing in the stock market? Here I am, sitting at my computer, and suppose I want a share of Apple - there isn't a button that says "Buy Our Stock" on their website. There goes my one idea. Where do I go and what do I do there?)
2 deficits of my own come to mind. I didn't learn the alphabet until middle school or so; I covered up my ignorance by knowing pairs of letters and simply looking it up whenever I needed to sort something. (In middle school I realized how silly this was and studied diligently until I could finally remember the alphabet song. For years after that, whenever I needed to know something, I would mentally sing through the alphabet song until I had my answer.)
Until 2 years ago or so, I didn't know the 12 months of the calendar. I got around this by generating a bunch of month flashcards for Mnemosyne. (The cards should be obvious, but if anyone really doesn't know how that would work, I can post them.) I'm still a little shaky but I more or less know them now.
These 2 methods may not be generally applicable.
I have the same deficit in most languages other than English.