Russy: Daniel, what are you doing?
Diggy: I need a toothbrush to brush my teeth.
Russy: That's yours. (points to a toothbrush sitting on the toothbrush holder)
Diggy: No it's not.
Russy: Yes it is. You used that yesterday.
Diggy: That's right. Yesterday's germs are not today's germs.
Russy: Nobody used that but you!
Diggy: Who cares? I use a new toothbrush everyday.