According to the definition given in the textbook, a definition of interpersonal communication that defines it as any face-to-face interaction between two people is omitting the notion of:

One day you learn that this same wealthy friend has become active in a community organization that serves the mentally challenged and their parents. you are told that her work with mentally challenged children consumes most of her weekends and a substantial part of her income and that she lives in modest circumstances. you find this hard to believe, and you suspect that somehow she is profiting from her involvement.