The Secret Life of Walter Mitty
First, During the first daydream that occurs, he gets interrupted by his wife, in a rather harsh way. By not standing up to her, he is showing how he is submissive. A victim of any sort is unlikely to stand up for themselves.
Secondly, coming out of his second daydream, he gets reprimanded by the garage man. After this incident , he is unable to speak any other word than "oh". Generally people who are victimized by others are people who are unable to get their words out.
Lastly, in his third daydream, the way he is unhappy. His unhappiness later makes his remember the dog biscuits. The way he is forgetful hints that victimization is a possibility.
Walter Mitty's actions lead to a liable assumption of victimization.
How to Get Over Fear and Find Courage