Teacher-Student Relationship

Students pay professors to teach them, just as they pay for any other service. But teachers give grades to students so the students can't act as if they are paying the teachers for a service. I find the relationship weird and uncomfortable. It is even more uncomfortable when you, like me, had to apply to get into a program. I was chosen along with 15 others or so to enter the Bachelors of Fine Arts program at BYU. Being accepted into the program means that you can get kicked out of the program also. I then have a feeling that I shouldn't upset the professor, instead of the professor worrying about upsetting me who is his customer.

Therefore, it seems that the professor has an innate intimidating power over his students. If the student vocalizes his disagreements against the professors opinions, the teacher might deliberately or perhaps even subconsciously reveal his dislike for the dissenters in the form of lower grades. How can this problem be solved?