My friend Mark told me his Chinese friend Peter invited him to lunch at his house last week.

Inside Peter's house, he saw pictures of frogs and dogs hanged on the wall. Peter told him he had to do ancestor worship (which is a common Chinese practice) before lunch.
He felt curious and asked, "Where are the pictures of your ancestors ? I can't see any except pictures of ugly frogs and dogs ?" Suddenly, Peter got furious and said how dare he insult his ancestors.

Later, Mark found out that Peter believed that the ancestor of his father's father was a frog, the ancestor of his father's mother a dog, the ancestor of his mother's father an ant and the ancestor of his mother's mother a mosquito.