As the communication progresses with trust, it is important for both teacher and student to be willing to address the taboo subjects, otherwise, there is never a genuine relationship. A teacher-student relationship can only last so long. In a one-on-one relationship, it can get pretty repetitive and boring, very quickly. Longer-length lessons are better for addressing topics in-depth and extracting from the lessons a more sophisticated understanding of a language and culture, as well as for understanding each other.