Katie

“Have you ever seen anything quite as pathetic?" said Malfoy. "And he’s supposed to be our teacher!"
Harry and Ron both made furious moves toward Malfoy, but Hermione got there first - SMACK!
She had slapped Malfoy across the face with all the strength she could muster. Malfoy staggered. Harry, Ron, Crabbe, and Goyle stood flabbergasted as Hermione raised her hand again.
"Don’t you dare call Hagrid pathetic you foul—you evil—"
"Hermione!" said Ron weakly and he tried to grab her hand as she swung it back.
"Get off Ron!"
Hermione pulled out her wand. Malfoy stepped backward. Crabbe and Goyle looked at him for instructions, thoroughly bewildered.
"C’mon," Malfoy muttered, and in a moment, all three of them had disappeared into the passageway to the dungeons.
"Hermione!" Ron said again, sounding both stunned and impressed.”
― J.K. Rowling, Harry Potter and the Prisoner of Azkaban

“I mean, you could claim that anything's real if the only basis for believing in it is that nobody's proved it doesn't exist!”
― J.K. Rowling

“Dumbledore watched her fly away, and as her silvery glow faded he turned back to Snape, and his eyes were full of tears.
"After all this time?"
"Always," said Snape.”
― J.K. Rowling, Harry Potter and the Deathly Hallows

“Mr. Moony presents his compliments to Professor Snape, and begs him to keep his abnormally large nose out of other people's business.
Mr. Prongs agrees with Mr. Moony, and would like to add that Professor Snape is an ugly git.
Mr. Padfoot would like to register his astonishment that an idiot like that ever became a professor.
Mr. Wormtail bids Professor Snape good day, and advises him to wash his hair, the slimeball.”
― J.K. Rowling, Harry Potter and the Prisoner of Azkaban