It's no secret that Aaron Sorkin likes to re-use his favorite lines. Though, to be honest, even I would not have guessed that he had used the derisive phrase "You think?" roughly 20 times, as the video below rather impressively demonstrates.
Kudos, too, to drfunky17, as this particular YouTube user calls himself, for bringing in Bulworth (the work Sorkin did on that script is uncredited, but widely acknowledged), Sorkin's recent commencement address, and the Tom Hanks Oscar speech from which Sam Seaborn stole one of his better lines.
(Bonus for Sorkin obssessives: Keep an eye out for John Gallgher, Jr., who had a small part in the West Wing episode "20 Hours in America." He's now one of the leads on The Newsroom.)