Typos are the the worst.
Just for fun, here are some classic funny typos that prove you need to do a final round of proofreading. (And yes, I know I'm sitting in a glass house throwing rocks.)
And because I’m a historian, I particularly liked this one for lack of basic fact-checking:
Hat tips: The Poke, AdWeek, Zazzle, Infinite Monkeys, Zombietime
