Aesop's Fables
#105 The Flea and the Ox
A Flea thus questioned an Ox: "What ails you, that being so huge and strong, you submit to the wrongs you receive from men and slave for them day by day, while I, being so small a creature, mercilessly feed on their flesh and drink their blood without stint?"
The Ox replied: "I do not wish to be ungrateful, for I am loved and well cared for by men, and they often pat my head and shoulders."
"Woe's me!" said the Flea; "this very patting which you like, whenever it happens to me, brings with it my inevitable destruction."