You're playing right wing on a defensive zone faceoff. Puck drops you skate out and cover the left point.
Easy enough assignment, right?
Unless you're (for example) me. Puck drops, I skate hard to cover point, forget to stop, go sliding right past him, he snatches puck, takes slapshot.
I don't need to tell you the puck where ended up.
Lesson for fellow idiot beer leaguers: it's much easier to cover the point if you're not 10 feet in back of him.