At first glance, Irene is a responsible and contributing member of society. She has a few complaints about things, but who doesn’t? As she tells her story it becomes more clear that writing endless letters of complaint is practically her only social interaction.
As Irene tells her story with the unmitigated belief that she is right, the audience begins to see her concern for the behavior of others is evolving quickly into something less benign.
Alan Bennett has described his characters as “artless narrators” who, like Irene, are blinded by their own perspective, and unable to see their story veering off course.