No good can come of association with anything labelled Gwladys or Ysobel or Ethyl or Mabelle or Kathryn. But particularly Gwladys.

The line exemplifies Wodehouse’s comic habit of treating names as social signals and as triggers for farcical prejudice. By declaring that “no good can come” of women with certain ornate, old-fashioned, or affectatiously spelled names—and then singling out “Gwladys” as worst of all—the speaker reveals more about his own snobbery and superstition than about any real person. The humor comes from the mock-serious tone of a sweeping moral law applied to something as arbitrary as a label, and from the rhythmic escalation to a punchline. It also plays on the Wodehouse world’s recurring anxiety about romantic entanglements and the “dangerous” woman as a source of chaos.