Amanda is an abandoned wife, that is the truth. She talks about her youth in Blue Mountain when she had 17 gentleman callers in one day, that I think is illusion. The fact that she married Mr. Wingfield, who she says was a charmer, instead of one of the other suitors she claims to have had leads the reader to believe that maybe there were not as many callers as she likes to remember she had. Her illusion, her inflated memory of her youth helps her deal with her present, which is dim and lacks hope of any kind for herself, Tom or Laura.
Tom is an angry young man who feels trapped by his responsibility to his family. He both resents and admires his father for escaping the incessant nagging of his mother, but feels abandoned just the same.
Tom's illusion comes in the form of his belief that he could actually find peace and a happy life if he just walked away from his nagging, overbearing mother. Even though he walks out on them at the end of the play, he is never rid of them, the illusion that he thought would rescue him has only created a spectre of his suffering sister ever present in his mind and heart.
He lives a life consumed by guilt and shame, he cannot go back to see his mother and sister because of his mistaken belief in the illusive behavior that his father modeled and he imitated.
Tom pretends to be a part of his family when in fact he loathes his mother and I think cares very little for his sister in any genuine way. If he cared for Laura with sincerity, he would have given more respect to his mother's request for him to bring home a gentleman caller for Laura, instead, he mocked the request put no effort into finding out anything about the man he invited to dinner and then made excuses when he found out from his mother that the man was engaged to be married.
Everything with Tom is an illusion, he pretends to work at the warehouse, when his mind is miles away longing to be a poet. The only honest and truthful thing he does is leave at the end of the play, instead of complaining about leaving, he really does it.
For me the most genuine person in the play is Laura, even though she lives through the glass menagerie that fills her world, she is what she is, she does not suffer, she is content with her life, it is her mother who fears for her.
Jim, the only link that the Wingfield family has with reality, brings a fresh realistic approach to the apartment when he comes over for dinner. He is a well grounded individual who accepts a dinner invitation without ever knowing that he is intended to be introduced to Tom's sister. Jim is innocent, Tom only uses him to get his mother off his back, to get her to stop nagging him, so he can leave the family, so he can become like his fathernd walk out the door and desert his family.