In Tennessee Williams's play A Streetcar Named Desire the character of Blance Dubois is a broken woman who has lost basically everything in her life. She has lost her good reputation due to several sex scandals including some that involve students. She has lost her teaching job, her family's plantation home, and her parents. Now all that she has is her memories and the mercy of her sister, Stella, who lives with a misogynist husband named Stanley.
There is a clear indication that Blanche does desire happiness, despite of it all. The problem is that she continues to act in her ways in order to achieve that happiness when it is clear that it is the way that she acts what gets her in huge trouble in the first place.
She does accommodate her personality, but only to a point. She tries to be charming to Stanley and his friends assuming that they will understand her attempts at creating Southern charm. She also does her best to help her sister cope with her husband and her pregnancy, but only by defying Stanley, which is a capital mistake in the Kowalski household. Furthermore, she tries to play the genteel woman with Michael only because he is her last hope, not really because she loves him.
Concisely, there is a disconnect between Blanche's true desires and her possibilities for them. All this is caused by her inability to change her behavior from passionate and dramatic to calm and sensical. However, in Blanche's world being calm and collected as well as typical and unassuming does not belong in her personality. This is what ultimately causes her happiness to miss her.