When there are disagreements, I am always told that the right way is to focus on the issue, not the person. Only by doing so, you could maintain the peace while solving the problem.
Now, I think it's not an absolute truth, whether you should focus on the issue or the person, it depends.
Obviously, it's not suitable for my current situation: the teacher is your boss, not your mentor.
If a teacher only cares about his project outcome rather than progress as well as scientific guidance, he convinces you that it's right because he only focuses on the issue, not the person. Sorry, I disagree.
For a teacher, he should focus on the person, his students whose purpose is to sharpen his or her mind in school before getting an official job. If he focuses on the issue, the profit works of a teacher are infinite because he makes a living for that, there is no student unique for a teacher because anyone could get work done.
With this kind of view, years after years, students come and go, but teachers get used to letting hundreds of students repeat the same patterns, the same failures, and the same disappointment until graduation.
Please be more responsible, focus on the person, not the issue. A student under rational guidance may fail once, but he or she would win again and again later.