Everyone was seated around the table as the food was being served. When little Johnny received his plate, he started eating straight away.
"Johnny, wait until we've said our prayer," his mother reminded him.
"I don't have to." - the little boy replied.
"Of course you do." - his mother insisted. "We say a prayer before eating at our house."
"That's at our house," Johnny explained, "but this is Grandma's house and she knows how to cook."