The Secret Life of Walter Mitty
The author's text structure defines Walter Mitty as the very timide, uncontrolling, pushed around character that he is.
Wlter Mitty is easily pushed around
His wife makes him put on his gloves. Additionally, the garage worker yells at him to tell him to get out of his car, rather than being polite and helpful.
He is timide and shy
Walter Mitty never fights back to anyone who is disrespecting him. He does what he is told even if he does not want to, like when the wife makes him put on the gloves. It's not until the end that Walter Mitty stands up for himself.
Lastly, Walter is very uncontolling and embarrassed by himself
Walter Mitty always daydreams for an escape from life. He can not control when these start, they are triggerd by the events and surroundings of Walter Mitty. At one point, Walter was so embarrassed by himself and the fact that he couldn't chain his tires, that he decided he wanted to wear a sling, just to convince the workers that he physically could not chain his tires.
Walter Mitty's characteristics are deffined through the text structure.