Here's a question: what movie lines became famous and popular before the movie came out, based solely on the trailers?
The one that comes to mind immediately is "You can't handle the truth!" from A Few Good Men. Because of the endless clips of that line in the trailer and the TV spots, everybody everywhere was quoting and even parodying that line before the movie had even opened. (I guess the line was also familiar to those who had seen the play, but most people were hearing it for the first time via the trailer.)
Another was from the trailer for The Godfather, Part III: "Just when I thought I was out, they pull me back in!" This was already one of the most-parodied lines in the movies before the movie came out; however, the actual movie was so disappointing that the line quickly became less quoted and less parodied -- because it was more fun hearing it in the trailer than in the actual movie.