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. RowlingAmazing, how much more difficult it was to extend his arm twelve inches and touch her hand than it was to snatch a speeding Snitch from midair.
J. K. Rowling