He had the look of one who had drunk the cup of life and found a dead beetle at the bottom.

Wodehouse’s simile turns disappointment into farce: “the cup of life” evokes a grand, almost poetic metaphor for experience and fulfillment, but the discovery of a “dead beetle” at the bottom punctures it with something petty, ugly, and absurd. The humor comes from the violent contrast between elevated expectation and trivial revulsion, capturing a particular kind of disillusionment—when one has gone through the motions of living (or pursuing some hope) only to find the payoff not merely lacking, but actively nauseating. It’s also a comic portrait of visible misery: the character’s face advertises that he has reached the end of something and found it grotesquely unsatisfying.