Pritchett's style as a narrator is quite unique in that it focuses more in the interaction of the characters rather than in the narration of a plot. This means that the actions and reactions of the characters are what actually move the plot forward while also creating an atmosphere that goes hand in hand with the mood of the characters. In "The Fly in the Ointment" the mood is set almost instantly through Harold's thoughts. Immediately we can sense the uneasiness of his visit, and the fact that he is doing "something"against his will.
Better not arrive in a taxi, he was thinking. The old man will wonder where I got the money.
The main character, Harold, is about to offer his financial help to his father. What would otherwise be considered as a good act is ruined by the fact that the father is completely unworthy of his son's kindness. The fly in the ointment, in this case, is that a good deed will not produce anything positive: instead, it will be the beginning of a very ugly conversation that will include humiliation, shame, and pain. The father's shameless love for money has ruined things that badly, just as a small fly would ruin an entire ointment.
Another salient fact about V.S. Pritchett's writing style is that he easily switches from one character to another, while preserving the atmosphere of the story, and easily switching perspectives. While this occurs, Harold and his father still come out as two completely different forces of energy; Pritchett is effective in showing that the father's energy completely consumes that of Harold's. The reader can feel that the father's switch from mellow, to hard, to almost evil, completely affects Harold and weakens him.
"Come in, Professor," said the father. This was an old family joke. He despised his son, who was, in fact, not a professor but a poorly paid lecturer at a provincial university.
There are no winners in this story; there is no beginning, middle, and end to the dynamics of the main characters: it is the essence of their treatment of each other, the delineation of their roles, and the power that one character has over the other what Pritchett really wants to illustrate in his writing. This is the reason why the story is accurately titled "The Fly in the Ointment".When the literal fly enters the plot and the father cannot kill it, the allegory is that the father cannot get rid of his main problem: that he is insensible and money-hungry.
As an idiomatic expression "the fly in the ointment" refers to a problem that is not big, just annoying enough to ruin everything altogether. The father's lust for money has ruined what could have been a chance to repair the relationship with his son who, after all, has demonstrated loyalty by going to offer his financial help. Hence, the appropriately-titled story "The Fly in the Ointment" explores the effects of what one tragic flaw can exert on something that should be valued, such as family unity.