Mood is defined as:
The atmosphere that pervades a literary work with the intention of evoking a certain emotion or feeling from the audience.
The mood of “Where Are You Going, Where Have You Been?” begins with Oates' description of Connie. She is fifteen and believes that everything revolves around her and her looks. She is not very mature. She believes she is grown up enough, for example, to hang out with the older kids at the drive-in restaurant across the highway, but she does so without her mother's permission or knowledge. Frankly, Connie is really very childish. The author presents Connie's attitude:
Her mother, who noticed everything and knew everything and who hadn't much reason any longer to look at her own face, always scolded Connie about [glancing into mirrors...]
...Connie's mother kept picking at her until Connie wished her mother were dead and she herself were dead and it were all over. "She makes me want to throw up sometimes," she complained to her friends...
It doesn't take long before the reader understands that Connie has little respect for her mother; she dismisses her sister because she is "so plain and chunky and steady;" she hates her mother's control over her life; and, she sneaks out where she should not go. And being pretty is more important than anything else in the world. She likes to draw attention to herself: we can assume, the attention of a boy:
She wore a pullover jersey blouse that looked one way when she was at home and another way when she was away from home.
Connie believes in things that she sees in movies and hears in love songs. But life is often not like a love song—she attracts the attention of a creature she doesn't even know exists.
By the time Connie arrives one particular night at the drive-in restaurant, the mood may be found in the reader's response. One may be annoyed, entertained, sympathetic or even impatient: she is nasty toward her mother and sister. She does not help even though everyone else in her house contributes in some way. Connie daydreams and studies herself in the mirror all day.
By the end of the story, however, the mood has changed drastically. The reader may be puzzled as Connie is at first when the two young men who show up at her house—the only thing she does care about is how she looks. She catches Arnold Friend early on in two lies: both about how old he is, but she isn't worried. She notices details about him that send negative signals, but Connie, who knows nothing of someone like Arnold, continues to chat and question—all the while he is spinning a sticky web, playing mind games with her to control her. He is slick and practiced. The mood alters—something is off about him. He pretends to be relaxed: he must be nervous about something. He orders her to come outside but she won't. He refuses to leave; Ellie offers to rip out the phone lines. Arnold knows she's alone. And then he threatens to "hurt" her family. His meaning is clear.
By the story's end, Connie has gone beyond terror. She feels empty. She knows she won't see her mother again and that she'll never sleep in her bed again.
The reader has seen evil:
I'll tell you how it is, I'm always nice at first, the first time. I'll hold you so tight you won't think you have to try to get away or pretend anything because you'll know you can't.
Because while this is fiction, it is based on a true story and so the sense of horror does not dissipate when the book is closed.