In A Streetcar Named Desire the part that Tennessee Williams' life plays in the text is fairly large. The issues of homosexuality, nervous breakdowns and problems with drugs and alcohol are found in the text, and anything on his life. These themes/ issues are predominant throughout the book, as they were throughout Williams' life.
His father withdrew him from university to work at the International Shoe Company, where he met Stanley Kowalski, who Tennessee Williams' has plastered all over A Streetcar Named Desire. Perhaps, Tennessee saw what Stanley was like on poker nights (he acquired a gambling habit himself at some stage of his life). .
The setting in the text may have been influence by the time he lived in New Orleans after he finished at the University of Iowa. Quoting A Streetcar Named Desire: The Playwright (http://hipp.gator.net/scarplaywright.html): 'He was noted for bringing to his audiences a slice of his own life and the feel of the southern culture. Elia Kazan said of Tennessee: "Everything in his life is in his plays , and everything in his plays is in his life.'.
I believe his life experience gave him the ability to write the dialogue with great insight, impacting on the flow of the book and if anything making it much better than if he was trying to imagine what a wife with a violent husband would say (his parents often argued violently), or how someone might react to that (he often encouraged his mother to leave his father). .
A personal interest/experience in the themes/issues and characters would not have harmed A Streetcar Named Desire, but rather helped make it the text it is.