1. Those Mailboxes That Aren't Really Mailboxes
You know, those grey or green boxes that look like mailboxes and are usually nearish mailboxes, but don't actually accept any mail. What are those? You've wondered for years, but never bothered to look up because you didn't know what they were called and didn't really care that much. Well, according to a bunch of unreliable answers on the Internet, and this somewhat-more-reliable message board from 2003, they're called "relay boxes" and are where letters are stored by one mailman to be picked up by another mailman so the second mailman can deliver them. Or something like that. They're mostly not used anymore because they seem highly inefficient, but the boxes are still there to taunt you when you're trying to find a mailbox so you can pay your rent.