Failure is impossible for high school students! (No, really)

[boba]

My pay is always attached to my performance. If I don't perform, I don't get paid. At all. I get fired.

That's not quite fair to teachers, though. They've got to deal with little devils who are actively degrading their performance.

It's completely fair, same as a salesman paid on commission. If you can't do the job (either one) effectively, then find a job you can do well or get paid less than others because you perform less than others.