A store that is popular with newlyweds runs a wedding gift registry. Five minutes before closing time on a Sunday, a young couple enters the store and wants to register—a process that usually takes 30 minutes or more. A sales associate advises the couple to come back when they have more time, even though a recent memo from the store's regional manager specifically instructed store personnel to stay after closing time to help such customers. Which key element of the marketing concept is the main problem area in this situation?