An object at rest will remain at rest and an object in motion will remain in motion unless acted upon by an outside force. Friction slows down a moving object because it is a force against motion. Three types of Friction. Rolling Friction - when an object rolls over a surface. Generally it takes less force to overcome rolling friction than sliding friction.
Friction is necessary - Imagine trying to walk or drive a car without friction.
It would be impossible to start moving without something to push off of, and once you were moving it would be impossible to stop. The hovercraft wants to keep going. If you only stop the board the person goes flying. When you hit the brakes hard on a bike or in a car. When going around a sharp curve your body presses against the person next to you or the door of the car.