1. They eat whatever they want.

2. They dance like a maniac to random music.

3. They trash their house.

4. They rob a bank and hold a bunny for ransom.

5. They reenact a scene from their favorite movie/tv show.

6. They eat off the floor and don't clean up afterwards.

7. They invite their friends over.

8. Pineapples.

9. They feed the squirrels an Xbox.

And finally...

10. They explain their mess to their parents when they get home...