Why is kindness the liver and lungs of a donkey?

As the saying goes, "kindness is like a donkey's liver and lungs": kindness is not understood and misunderstood as kindness. Donkey liver and lung: vicious and cruel. Source: Ming Lanling Xiao Xiaosheng's "Jin Ping Mei Hua thorn" The twenty-eighth time: "You see that I made a donkey liver and lungs with good intentions, but you picked me up and only said that I would go." Source: "Surprise at the Second Moment" Volume 4 "Why are you so greedy and thinking about eating alone ... I don't know how the donkey's heart and dog's lungs are born." A donkey in a servile position is stubborn. In ancient times, it was often compared to the back of the head, with heartless heart evil and no conscience, only liver and lungs. Another repost lyg6 186 18 [advanced extreme] Anyone who has tasted donkey meat knows that the liver and lungs of donkeys are the most unpalatable (bitter and astringent), so the price is relatively cheap. The price of "kindness" is much more expensive than the liver and lungs of a donkey. People use this sentence to express the misunderstanding of stealing concepts between people.