A man walks into a store

MAN: I'd like to buy some dog food.
CHECKOUT LADY: Do you have a dog?
MAN: Yes.
CHECKOUT LADY: Where is he?
MAN: He's at home.
CHECKOUT LADY: I'm sorry, I can't sell this dog food to you unless I see the dog. Store policy.

The next day the man returns

MAN: I'd like to buy some cat food.
CHECKOUT LADY: Do you have a cat?
MAN: Yes.
CHECKOUT LADY: Well...where is it?
MAN: He's at home!
CHECKOUT LADY: Sorry, I can't sell you this cat food unless I see the cat.

The next day the man returns

CHECKOUT LADY: What's in the bag?
MAN: Put your hand inside.
CHECKOUT LADY: Hmmmm....It's warm and moist! What is it?
MAN: I'd like to buy some toilet paper!!!!!

ouch , that was a nasty and good one