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. RowlingRemember, if the time should come when you have to make a choice between what is right and what is easy, remember what happened to a boy who was good, and kind, and brave, because he strayed across the path of Lord Voldemort. Remember Cedric Diggory.
J. K. RowlingDumbledore paused, and although his voice remained light and calm, and he gave no obvious sign of anger, Harry felt a kind of chill emanating from him and noticed that the Dursleys drew very slightly closer together. โYou did not do as I asked. You have never treated Harry as a son. He has known nothing but neglect and often cruelty at your hands. The best that can be said is that he has at least escaped the appalling damage you have inflicted upon the unfortunate boy sitting between you.
J. K. Rowling