Long ago, a mother-in-law became unhappy because she felt her son-in-law was not taking good care of her daughter. Rather than confronting him directly, she decided to send him a subtle message through food—as many Thai mothers traditionally do! She boiled and fried some eggs, then served them with a sweet, sour, and salty tamarind sauce. When the son-in-law asked about the dish, she jokingly called it "Kai Look Koei," which literally translates to "Son-in-Law Eggs."