Cain has noted that people of different temperament who become involved in personal relationships—possibly drawn to one another by a sense that each completes the other—can encounter misunderstanding and conflict.
Cain menulis bahwa orang berkepribadian lain yang terlibat dalam hubungan pribadi—yang mungkin tertarik karena merasa saling melengkapi—mudah diterpa kesalahpahaman dan konflik.