Young cats, especially, get it alot. I remember when mine was young, she would just tear across the house. Literally. You could hear the carpet shredding as she zipped by. She liked to play tag with peoples' feet, too. And beware going up or down stairs...she WILL go for your legs. We used to have a toy on a string that we would use to distract her near the stairs at all times. I sort of think of it as paying the ferryman to cross the river Styx.