The scene in which Montag comes home to find his wife, Mildred, had overdosed on her sleeping pills shows us something of Mildred.  She must not be a happy person to have taken so many sleeping pills. Either she wanted to die or she couldn't sleep due to problems bothering her and took lots of pills to overcome her thoughts.  The next day, Mildred denies having done any such thing which shows us that she lives her life in denial.  That same scene shows us her absorption with television.  That is a major aspect of her personality.  When Montag stays home from work after witnessing the old woman who would rather die in a fire with her books than live without them, Mildred is upset.  She doesn't want Montag to stay home.  She likes her routine, easy life.  She doesn't want anything to interfere with her meaningless existence because it's an easy existence that requires no thinking and no confrontation with the problems of the world.  Montag staying home interrupts her life and the things he says bring forth the society's problems.  This same aspect of her personality is brought out when Montag reads to Mildred and her friends.  Again, she does not want to face reality and Montag is trying to make her do that.