"Apparently Ronald Reagan was amused by Doc Brown's disbelief that an actor like him could become president, so much so that he had the projectionist stop and replay the scene. He also seemed to enjoy it so much that he even made a direct reference of the film in his 1986 State of the Union address: "As they said in the film "Back to the Future", 'Where we're going, we don't need roads.'""
https://www.imdb.com/name/nm0778734/