Critics find that some of the characters are being satired in their initial presentation. Pick two characters.
Even years after reading the story, the two characters that jump to mind are two of the religious ones: The Monk and the Prioress, Mdme. Eglentyne.
With Mdme. Eglentyne, even though she is a religious and supposed to be humble woman, she conducts herself as aristocratic, uses her French to impress, and her prim and proper mannerisms are a bit curious. She also comes across as over-dramatic and a bit of a fake.
In the case of the Monk, Chaucer asks an interesting question to explain why the Monk is rebellious to the rules of no-hunting. He asks "why should a monk go crazy with study and rules"- Meaning that maybe in his opinion, no monk follows the rules they preach, and they may not even be that smart.