Professor, why couldn't we just Apparate directly into your old colleague's house?' 'Because it would be quite as rude as kicking down the front door,' said Dumbledore. 'Courtesy dictates that we offer fellow wizards the opportunity of denying us entry.
J. K. RowlingThing was' he faced them, and Harry was astonished to see that he was grinning, 'they bit of a bit more than they could chew with Gran. Little old witch living alone, they probably think they didn't need to send anyone particularly powerful. Anyway' Neville laughed, 'Dawlish is still in St Mungo's and Gran is on the run. She sent me a letter,' he clapped a hand to the breast pocket of his robes, 'telling me she was proud of me, that I'm my parents' son, and to keep it up
J. K. RowlingDeliberately causing mayhem in Snape's Potions class was about as safe as poking a sleeping dragon in the eye.
J. K. Rowling