Illiteracy? What does that even mean? Laugh out loud every time. I know it's not exactly a hidden thing within the show, but Charlie not being able to read gets a chuckle out of me every episode it happens. It's so, well, stupid that I will always find that sort of comedy hilarious. Not only that but they find a way to bring it up in a different way. Whether it's him leaving notes, trying to read even the 'pirate' sign on a door. It's the best show out there for a reason.