'The Ass Eating Thistles', an illustration by JVL in Aesop's Fables, Jonathan Cape, 1989, page 64.
Here is the fable, as told by Charles Draper in 1760.
The Ass Eating Thistles
AN Ass, loaded with provisions, meeting with some Thistles, began to devour them with much greediness. In the midst of his coarse repast he said thus: The provisions I carry cannot seem more exquisite to delicate palates, or more agreeable to their appetite, than this harsh thistle is to me.
Moral: One person’s meat is another person’s poison.
Text: Charles Draper (116, 1760).
Selected parallels: Babrius 133. Chambry 280. Perry 360.