Don't Bring Your Mom Sour Fruit

I took a morning ride with a teacher last week. We rode about 24 km up into the mountains near Wuci. Before climbing into the mountains we took a break at a temple. Like temples all over the country there is an oven for burning ghost money. Ghost money is fake money that is burned as an offering to relatives who have died. Anyway, there is a picture on the side of the oven of a man being stopped by two robbers. The man has two baskets of fruit. One is filled with red fruit and the other is filled with green fruit. The man was planning on bringing the green fruit, which is sour fruit, to his mother and keeping the red fruit, the sweet fruit, for himself. I'm not sure how the robbers get involved, but I gather that the morale is don't bring your mother sour fruit. This is a very popular story and the teacher tells me that he tells this story to his kids.