Remember when you were in school and thought your teacher knew everything? Boy, were you wrong.

The YouTube channel list25 has made this video explaining 25 things you learned in the classroom that simply aren't true. Some, like the food pyramid, are a result of advances in research that wound up debunking popular thinking, while others are disheartening, like the idea that you must get good grades in order to succeed in life. Harvard dropout Mark Zuckerberg can probably shed some more light on that one.

Still, some others we knew were fibs when they were being hammered into our heads, including the notion that we have to learn math without a calculator because we won't always have one on hand. Even pre-iPhone we somehow knew this was ridiculous.

And then there's need to learn cursive writing, although, to be fair, that is coming back in style.

Those are just a few of the lessons taught in school that are about as out of touch as the need to climb the rope in gym class. What do you think? What were some things you learned that you have since discovered are just plain false?

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