All of us have our personal horrors. Without having read any history on why George Orwell wrote 1984, and because you asked about my opinion, I give it to you here before it becomes tainted by what the outside world thinks. And the outside world, that is, the world outside my head, must think a lot since 1984 is considered a masterpiece. 

It sounded to me very much like a materialization of George's deep seated fear (stirred up by Stalin and his comrades, and Hitler perhaps too), this idea that an abstract entity, a thing that is a political concept, can crush you into nothing, to the point where you betray yourself. Politics here is only a vehicle. The horror is deeper. The horror is that for humanity and for what we are capable in the face of chaos. Life is chaos. So evolutionary we've been developing our brains to try and understand what the hell we're going on this earth, who we are, and what does it all mean. If you think about the picture that the Ingsoc Party in 1984 portrays, it's precisely the utopia of an absolute certainty of every bloody thing at all times. The past is gone, the future is always accurately predicted, hence the self-delusion that both statements are true is the perfect escape. You could almost call it a perfect religion.