What's one thing you learned in elementary school that you still don't get?

For me, it's why there's a Washington D.C. and also a state called Washington. I never understood why they had to have two major places in the United States pretty much named the same. And the fact that people can say, "yeah I'm traveling to Washington" and it could mean either! Even though most people do say DC, on the east coast folks still reference it as simply "Washington".

What are you still hung up on? Make your elementary school self feel vindicated.