The central character, or the protagonist, of Tennessee Williams's The Glass Menagerie is Tom Wingfield. Tom finds himself in conflict with his own character traits at times, so he is sometimes his own antagonist. In addition, Tom is in conflict with tradition and its illusion, as represented by his mother, Amanda, and her values and dreams of a "gentleman caller." Therefore, Amanda is an antagonist to Tom, as she complains that he will not act as "normal people" do, and she tries to force Tom into the role of provider.
In truth, all three characters, Laura, Tom, and Amanda, pay an emotional price because they dwell in illusions. Laura creates an illusory world with her glass menagerie, Tom escapes into the novels that he reads and the movies that he attends, and Amanda retreats to the traditions of her youth and the concept of the gentleman caller who will rescue her daughter and support the family.
AMANDA: Why can't you and your brother be normal people? Fantastic whims and behavior. Preposterous goings on (Scene 6)!
Yet, it is Amanda who blocks Tom from being himself by confining him to the warehouse job, and by making him feel responsible for the care of his sister and mother.
TOM: I'm starting to boil inside. . . Whenever I pick up a shoe, I shudder a little thinking how short life is and what I am doing (Scene 6).
The protagonist Tom is not willing to sacrifice for his family. Yet, he feels guilt as he flees the confinement of his life and the emotional toll of living in a world of illusion.