Who said "I expect perfection in my classroom, not mediocrity."?

This quote is attributed to Severus Snape.

I expect perfection in my classroom, not mediocrity. - Severus Snape

"I expect perfection in my classroom, not mediocrity."

Severus Snape Leadership

"It is our choices that show what we truly are, far more than our abilities."

"Dunderheads. All of you. Particularly you, Potter."

"I can teach you how to bottle fame, brew glory, even put a stopper in death."

"One sip of this potion would make a man invincible."

"A leader must be fair and just."

"Integrity is everything."

"One must take responsibility for one's environment."

"In this house, I make the decisions"