Power
Here's where you cackle, rub your hands together, and whisper menacingly, "Pop quiz, my little minions!"
Your students will squeal in delight when you postpone a deadline. They'll groan and glare when you give them extra homework. It all depends on what sadistic tendencies you exhibit. In the end, the power you exert should contribute to a single goal: helping your students learn.
They'll probably accuse you of cohorting with the devil to come up with new ways to torture them, but if they learn, who cares if they hate you? We know you'll only assign homework if it will help them learn a new language. Why? Because even in teaching, there are checks and balances. The more homework you assign, the more you'll have to grade. Ay, there's the rub.
On the flip side, there are always students who go out of their way to exert power over you and make your life miserable. It's Larry Contrary's turn to chuckle maliciously. He's writing out his report in handwriting that could easily be mistaken for Egyptian hieroglyphs.