“I only want power so I can get books.”

“Okay, so either (a) I just teleported somewhere else entirely (b) they can fold space like no one's business or (c) they are simply ignoring all the rules.”

“I don't want to rule the universe. I just think it could be more sensibly organised.”

“He wanted to write someone and demand a refund on his dark side which clearly ought to have irresistible magical power but had turned out to be defective.”

“You will find ambiguity a great ally on your road to power. Give a sign of Slytherin on one day, and contradict it with a sign of Gryffindor the next; and the Slytherins will be enabled to believe what they wish, while the Gryffindors argue themselves into supporting you as well. So long as there is uncertainty, people can believe whatever seems to be to their own advantage. And so long as you appear strong, so long as you appear to be winning, their instincts will tell them that their advantage lies with you. Walk always in the shadow, and light and darkness both will follow.”

“If the box contains a diamond,I desire to believe that the box contains a diamond;If the box does not contain a diamond,I desire to believe that the box does not contain a diamond;Let me not become attached to beliefs I may not want.”

“Mr. Malfoy is new to the business of having ideas, and so when he has one, he becomes proud of himself for having it. He has not yet had enough ideas to unflinchingly discard those that are beautiful in some aspects and impractical in others; he has not yet acquired confidence in his own ability to think of better ideas as he requires them. What we are seeing here is not Mr. Malfoy's best idea, I fear, but rather his only idea.”