looking for a thesis statement for The Secret life of Walter Mitty and The Glass Menagerie

A simple and accurate thesis statement involving The Glass Menagerie and "The Secret Life of Walter Mitty" would convey that we are ultimately responsible for finding our true identity using determination, rather than fantasizing about being different. This is true, even when we are forced to exist in a world that overbears us.
In both short stories, we find characters who have fallen short of the expectations society bestows upon them. However, rather than summoning determination and taking responsibility for changing their lives, these characters resort to fantasizing and deflecting their problems, thus perpetuating their fantasy lives.
Walter Mitty spends his life daydreaming about being a socially, physically, financially, and intellectually superior version of himself. The presence of his pushy wife makes things worse for him; he seems to be helpless and less motivated by her in his desire to be better. However, his tragic flaw is that he lacks the determination to change. Even at the end of the story, we see no redeeming qualities in him. He remains a very flat character. Even something as mundane as having to face his wife would make him break into a daydream.

He took one last drag on his cigarette and snapped it away. Then, with a faint, fleeting smile playing about his slips, he faced the firing squad . . . Walter Mitty the Undefeated, inscrutable to the last.

In The Glass Menagerie, several characters lack the will to change. Amanda is unable to move away from her past, and she consistently brings up memories of the better years she spent as a young woman. Jim, a former high school jock, is still living up to his past as a “popular kid” and has unrealistic dreams for the future.
Laura, her daughter, has been so overprotected by Amanda that social anxiety has taken the best of her. Moreover, Laura allows a physical handicap that makes her limp to define who she is as a person. As such, she acts more like a dependent “cripple” than like what she truly is: a young woman with every chance to be independent and make it in the world, if she truly wanted to.
Instead, Laura spends her time listening to the phonograph and tending to her glass menagerie. In doing this, she is deflecting attention from where it should be placed. She prefers to take the easy way out and make up a world of her own, much like Walter Mitty.
Tom is also lost in identity. Even though he manages to escape his overbearing life, it does not seem as if he has entirely found himself. In both works, all characters lack an anchor of identity.