Friction is a force that opposes motion between two surfaces in contact.

Here's why the correction is important:

* Opposes motion: Friction doesn't *cause* motion, it works against it. If you try to slide a book across a table, friction acts in the opposite direction of your push, making it harder to move.

* Between two surfaces: Friction arises from the interaction between the microscopic irregularities of the surfaces that are touching.

Let me know if you have any other questions about friction!