One similarity between Ismene in Sophocles' play Antigone and Laura in Tennessee Williams's play The Glass Menagerie is their tendency to shy away from situations and their inability to act.
In the opening of the play, when Antigone comes to her sister Ismene with the proposition of jointly breaking Creon's law to give their brother Polynices a proper burial, Ismene shies away from the situation and begs Antigone not do it. Ismene's reasoning is that she and Antigone have already lost so many of their family members due to infamy and death that she cannot bear the thought of dying a horrible death herself:
And now the two of us, left all alone--
think how very horribly we will die
if we go against the king's decree and strength outside the law. (58-61)
Instead, she feels she must submit to the fact that she's a woman and therefore not strong enough to "fight with men" and must therefore "be ruled by more powerful people" than herself (62-63).
Similarly, Laura in The Glass Menagerie also feels she has no strength to do what she must do but for different reasons. Unlike Ismene, Laura has been left crippled by illness and feels that her crippled leg makes her look "freakish," just like her favorite glass unicorn among her menagerie looks "freakish" among the other horses (I.vii). As a result of feeling "freakish," she's too shy to be in the presence of others, especially when she feels she's being watched or judged. Hence, when her mother enrolls her in secretarial school, Laura nearly throws up the first time she must take a speed typing test and drops out of school. The problem is, since Laura also has no prospects for a husband, she has no means of providing for herself unless she gets a respectable job. But due to feeling different from other people, just as Ismene feels weak before other people, Laura is unable to do what she needs to do to give herself a good life.