A blurred photo is a ruined photo, right? Not necessarily. Blur conveys motion, something still images don’t usually do. A photo with a sharp background but a car that is blurred tells you the car was in motion. To take this kind of shot, keep the camera steady and snap the shutter at the moment the car crosses the frame.
You can also convey motion by turning this formula around: if you pan along with the moving car as you snap, the car will be sharp but the background will be blurred. A canine-oriented example is above.