"Everyone knows you're the only one You-Know- oh, all right, Voldemort, was frightened of." [McGonagall]
"You flatter me," said Dumbledore calmly. "Voldemort had powers I will never have."
"Only because you're too -- well -- noble to use them."
"It's lucky it's dark. I haven't blushed so much since Madam Pomfrey told me she liked my new earmuffs."

Harry Potter and the Philosopher's Stone - Chapter 1 : The Boy Who Lived
See this quote in the Pensive -