The narrator is not happy that he has been tricked into Simon Wheeler's story-telling antics. He is annoyed that he is stuck listening to these tales about Smiley's gambling. While he listens well, he is not amused, patient, or attentive.
The analogy is meant to show parallels between two sets of words. Fertile is to arable as vague is to clouded. If you understand either pair it can be used to decipher the meaning of the other pair you don't know.