In "The Fly," the boss has the wound of losing his only son reopened when an old friend visits. The boss tells his secretary not to let anyone interrupt him for a half hour. He puts his face in his hands and expects to cry, as he did all the time when he first got the news. We are told that "he wanted, he intended, he had arranged to weep."
The parallel structure, by repeating the same idea three times—that the boss had intended to respond by crying—emphasizes how much he expected that response and how odd it is when he doesn't have it. This repetition shows that, psychologically, he has reached a turning point in his grieving process and can no longer react the same way as he did. Something has changed over the years. While he tries to go back in time to the socially acceptable grief he once felt, that moment has passed.
Instead, as we see when he kills the fly, the boss's grief has turned into anger. He sadistically enacts on the fly the slow death—all the while telling the fly to be optimistic and keep on trying—that he feels has been cruelly enacted on him.
The story shows the unspoken grief and rage people felt in 1920s England over what most realized was the unnecessary waste of life in World War I and their repressed anger at the platitudes about hope they were expected to believe in.