It's Always Sunny In Philadelphia: 10 Best Recurring Jokes

It's safe to say that Charlie is a genius in his own right. The man might not have much control over his life, but he's very skilled at what he does. There are not many other gang members who can play multiple instruments, multitask a health inspection with a scam and survive so long in the sewers. With that being said, by conventional standards, he's far from being a genius.

It's made clear early that Charlie has no understanding of the written word and a "tenuous grasp on the English language in general" - as stated by The Lawyer. This has come up very consistently in the show, as Charlie's struggles to read have been a thorn in the side of the gang on multiple occasions.

For example, he accidentally left the closed sign on at the bar, has created terrible maps of the vent systems, and even accidentally entered the gang into a dance marathon with Paddy's Pub as the grand prize. This particular mistake led to the classic line, "your illiteracy has screwed us again".

Fans can only hope that Charlie learns to read one day, for his sake. But, for now, it's hilarious to see how his illiteracy causes havoc.