Harry said seriously to Umbridge:
"I'm sorry, Professor Umbridge, but I have to tell you that Hogwarts has never taught students useless things. Everything we teach has practical value.
So you must explain how to cast Defensive Charms in Defense Against the Dark Arts."
Umbridge had not expected Harry to give her so little face. However, wary of Harry's strength and afraid he would directly attack her in class and make her lose all dignity, she suppressed her anger and said:
"Mr. Potter, you are still young and do not understand what education truly is. So please do not interrupt a professor while she is speaking. I will teach you properly."
But Harry remained unmoved and repeated:
"Professor Umbridge, I am telling you solemnly that Defensive Charms must be taught in Defense Against the Dark Arts. I do not wish to repeat myself a third time."
Harry's blunt words finally made Umbridge snap.
Her fingers suddenly clenched around the pink lace cloth at the edge of the lectern, her knuckles turning white from the force.
Her cheeks puffed up like an inflated pufferfish, and a venomous gleam burst from her tiny eyes. Her syrupy voice abruptly sharpened, like fingernails scraping across metal:
"Mr. Potter, I have been speaking to you nicely, yet you have no intention of communicating with me at all. Fine, then let me tell you the truth!
Defensive Charms? The curriculum approved by the Ministry of Magic does not include such dangerous things!
Who do you think you are, Dumbledore's little messenger?
I am the professor of this class. What I teach and how I teach it is not for a student to dictate!
It seems you have been far too indulgent this summer... but never mind. I will make you understand that at Hogwarts, professors are