J.K. Rowling

"Yeah, Quirrell was a great teacher. There was just that minor drawback of him having Lord Voldemort sticking out of the back of his head!"
"Harry was left to ponder in silence the depths to which girls would sink to get revenge."
"Remember, if the time should come when you have to make a choice between what is right and what is easy, remember what happened to a boy who was good, and kind, and brave, because he strayed across the path of Lord Voldemort. Remember Cedric Diggory."
"I enjoyed the meetings, too. It was like having friends."
"Are you insane? Of course I want to leave the Dursleys! Have you got a house? When can I move in?"
"Nobody's ever asked me to a party before, as a friend. Is that why you dyed your eyebrow, for the party? Should I do mine too?"
"Why are you worrying about YOU-KNOW-WHO, when you should be worrying about YOU-NO-POO? The constipation sensation that's gripping the nation!"
"Curious indeed how these things happen. The wand chooses the wizard, remember...I think we must expect great things from you, Mr. Potter... After all, He-Who-Must-Not-Be-Named did great things — terrible, yes, but great."
"It does not do to dwell on dreams and forget to live."
"We are only as strong as we are united, as weak as we are divided."
"The Forbidden Forest looked as though it had been enchanted, each tree smattered with silver, and Hagrid's cabin looked like an iced cake."
"What she did have were Bertie Bott's Every Flavor Beans, Drooble's Best Blowing Gum, Chocolate Frogs, Pumpkin Pasties, Cauldron Cakes, Licorice Wands, and a number of other strange things Harry had never seen in his life."