During the Warring States Period, there was a musician named Gongming Yi, who played musical instruments very well.
There were a great number of people fond of listening to him play, and respected him very much.
One day, Gongming Yi saw a cow when he was having fun in the countryside.
He thought, "Everybody compliments my music. Why don't I play some music for this cow?"
He played a piece of elegant quaint music for the cow, but the cow just kept grazing the grass with its head down.
He played another piece of joyful music, but the cow still kept its head down to graze the grass and totally ignored him.
Gongming Yi was so disappointed and started to question his ability.
A passerby said to him,"It's not because your ability is bad. It is because the cow can not understand music at all."
Don't waste your time and breath. It's not worth casting pearls before swine!