What is a major theme in "The Secret Life of Walter Mitty" by James Thurber?

Marital conflict is a recurring theme throughout “The Secret Life of Walter Mitty.” Mitty is first pulled from his daydream of commanding a hydroplane in the Navy by his wife complaining that he is driving too quickly. He doesn’t bother to respond to his wife and continues to drive in silence. In fact, it isn’t until her tenth sentence of the story that Mitty responds to her, and when he does it is a protest: “I don’t need overshoes.” She ignores this and reminds him that he is no longer a young man, and his response is to race the engine. His methods of revenge against her actions are petty—after his wife suggests that he wear his gloves, he dons them and promptly takes them off after driving away.

Mrs. Mitty does not appear in the story again until the very end, but her presence is felt throughout. After a man parks Mitty’s car for him, Mitty recalls resentfully that she makes him go to a garage to have the chains taken off his car after he got them tangled around the axles. Later, having forgotten what his wife told him to get at the store, Mitty’s frustration appears to be entirely directed at her and the inevitable questions that will occur if he cannot remember what he needs to purchase.

Mitty’s resentment is on display throughout the story: it fuels his constant need to escape from reality. His incompetence in the real world, often pointed out by his wife, must be countered by Mitty’s brilliance in his daydreams.

Mrs. Mitty’s point of view is not given, but it is not difficult to understand her frustration. Having pointed out that her husband was driving too fast for her comfort—something that, it is implied, she has reminded him of previously—he doesn’t deign to respond. Of course she nags him to do the errands and reminds him to put on his gloves; it is difficult to imagine Mitty getting anything done without her guidance, much as he dislikes it. Mrs. Mitty seems to get the short end of the stick, if anything.

At the end of the story, having been left outside of a drugstore for a moment (he notes that it has been “more than a minute”), Mitty imagines walking toward a firing squad. The subtext is fairly clear: Mitty would prefer an honorable death by firing squad to his wife’s nagging.