Sometimes, they also serve another purpose.

Here is an anecdote to wrap up the narrative. It was said that a long, long time ago, there was a man who requested a meeting with Confucius (551-479 BC). He was refused a meeting, but thought of a plan. He sent a roast suckling pig to the master, and because Confucius was such a strict observer of courtesy, he finally agreed to meet the man.

Zhengzhou spicy duck tongues Ma Jian / for China Daily