Just smile

Guy: I want to buy dog food.

Seller: Do you have a dog?.

Guy: Yes

Seller: Where is it?

Guy: At home.

Seller: Sorry, i can't sell you dog food
unless i see the dog first, it is our policy.
The Next Day....
Guy: Do you have cat food?.
Seller: Where is your cat?.
Guy: It is at home.
Seller: Sorry, i can't sell cat food for you
unless i see the cat.
Two Days Later....
The Guy went there holding a nylon bag.
Seller: What is in your bag?.
Guy: Put your hand inside first.
(The seller puts his hand inside)
Seller: It's cold, what is it?.
Guy: It is my shit! I need toilet paper