The main insight I gained from 1984 was the linguistic stuff which was meaningful to me at the time because it would be years before I heard the Sapir-Whorf hypothesis. Also, Orwell eloquently expressed the idea that humans can be tortured to the point where we truly can believe anything. 2+2=5, indeed. I was familiar with the "Big Brother is Watching" meme before reading 1984 and was surprised to find the book's other insights much more powerful.

(It is interesting how 1984 has been more accurately prophetic than most dystopian fiction. See Jose Padilla, tortured by the US government to the point where he seemed to want to lose his own trial, he was upset that the proceedings were “unfair to the commander-in-chief”, from http://www.democracynow.org/2007/8/16/exclusive_an_inside_look_at_how , an interview with Padilla's psychiatrist. Also see the Orwellian names W and friends drafted for bills, and the surveillance state in the UK.)