The grandfather

I went to a shop to buy Janine a present. I said to the owner, "I'm looking for something for a little girl."

The man asked, "Is it your daughter?"

I answered, "No, my granddaughter. The only problem is, I don't know her size."

The man said, "What kind of grandfather are you? You don't know your own granddaughter's size?"

I said, "Whenever she wears a sari, she looks very stout and fat. But whenever she wears Western clothes, she looks thin and skinny."

Then I just picked out something, without knowing whether it was too small or too big.