In his mind, Walter imagines that he is the most capable man in the world. In his real life, he is quite incompetent. One might think that, at least occasionally, Walter would try to be competent and successful in his real life, but he doesn't do this. In fact, he purposely tries to avoid succeeding. It is ironic (situational) that he would go to such lengths to avoid success. Consider the scene in which he can't get the chains off his tires. Instead of learning from his mistake or learning from a professional, he chooses to avoid even trying in the future:
The next time, he thought, I'll wear my right arm in a sling; They won't grin at me then. I'll have my right arm in a sling and they'll see I couldn't possibly take the chains off myself.
Walter chooses to be heroic in his mind, but would rather appear like an invalid in his real life.
Note the final line of the story. It ends with "Walter Mitty, the Undefeated, inscrutable to the last."...
(The entire section contains 2 answers and 512 words.)