“Knock. Just knock. Why isn't she knocking? Do you think she knows how to knock?”— Jennifer Lee, Olaf (voice), Josh Gad, imdb.com
“When the door you have been knocking at finally swings open, you don’t ask why. You run through.”— Keith Eisner, Diane Lockhart, Christine Baranski, imdb.com
“It is vain to desire them to knock; they do not comprehend you and if they do, pay no manner of attention to it. It took me six weeks to teach my old Anna not to come in without knocking and leave and finally it was only by appearing to get into a most violent passion and threatening to blow out her…”— Aaron Burr, archive.org