Quote from : Harry Potter and the Sorcerer's Stone Book

Albus Dumbledore had gotten to his feet. He was beaming at the students, his arms opened wide, as if nothing could have pleased him more than to see them all there. "Welcome!" he said. "Welcome to a new year at Hogwarts! Before we begin our banquet, I would like to say a few words. And here they are: Nitwit! Blubber! Oddment! Tweak!" "Thank you!" He sat back down. Everybody clapped and cheered. Harry didn't know whether to laugh or not. “Is he — a bit mad?” he asked Percy uncertainly. "Mad?" said Percy airily. "He's a genius! Best wizard in the world! But he is a bit mad, yes. Potatoes, Harry?