The setting in The Face on the Milk Carton is important because it is so very normal. Janie lives in a suburban neighborhood in a nice, split-level, single-family home. Her house has all the amenities of a typical, upper-middle-class dwelling - "gleaming-white washer and dryer," stylish but serviceable furniture, photographs on the wall. The photographs show that Janie has participated in the usual family activities while growing up - gymnastics, Girl Scouts, family vacations. The neighborhood itself exudes a sense of security and stability; Janie's family is close to the family next door. Janie's family, the Johnsons, has lived in their house since she was small, and the Shields have lived in theirs longer than that; Janie and the Shields children always put the other's mother down as a contact on their school emergency cards. Janie's father is an accountant who coaches a middle-school soccer team in his spare time, and her mother is active in volunteer work with various organizations. Janie herself is preoccupied with the normal things that teenagers are interested in - school, getting her drivers' license, and establishing a satisfactory social life.
The setting is so normal it is actually almost cliche. It is the last place where one would think something as terrible as a kidnapping might have occurred in one of the characters' lives, making the possibility that it has all the more incongruous and difficult to accept.