What bothers Winston in 1984?
O'Brien calls Winston the "last man," and we might say that, fundamentally, what bothers Winston is the way the state strips people--and most specifically, he himself--of their humanity. He remembers, if dimly, his childhood before the revolution, and he knows people lived and acted differently. From the start of the novel, as symbolized in his purchase of a secret journal, he is trying to hold on to a piece of his humanity. He resents the endless intrusions of the Party into his life and clings to his individuality and remnants of autonomy:
It was assumed that when he was not working, eating, or sleeping he would be taking part in some kind of communal recreations; to do anything that suggested a taste for solitude, even to go for a walk by yourself, was always slightly dangerous. There was a word for it in Newspeak: ownlife, it was called, meaning individualism and eccentricity.
Winston pursues "ownlife" relentlessly. He wanders into Mr. Charrington's shop in the prole's section of the city. He writes in his diary out of view of the viewscreen. He buys a paperweight. Although altering history is his job, for he rewrites newspaper articles to accord with whatever is the current version of then truth, he is obsessed with the idea that there is an objective material reality that transcends the Party's ever-changing version of it. He tries to remember and capture pieces of the lost world of the past, be it through a nursery rhyme or a paperweight. He dreams of the fall of Party and of a secret organization that will bring it down--or of the Proles rising up. He expresses his dissatisfaction with the Party and desire for an individual life apart from it in his affair with Julia. From the point of view of the Party, which wants to possess every iota of a person's body, mind and soul, we can see the extent to which he truly transgresses and is an enemy to the state. He is bothered by the state and the state by him.
In 1984, Winston is bothered by the fact that he does not have any information on the past. Winston was fortunate enough to have been born during a time when Big Brother had not yet come into power. He has vague memories of his life prior to the development of the Totalitarian state which Oceania has become; however, he is unable to make sense of them due to the extreme manipulation from The Party. Winston even seeks out knowledge about the past from one of the proles at an old pub, but he is not able to recover any information that is of value to him. He is so bothered by this lack of awareness of his past that he is willing to risk his life (the Thought Police will certainly punish him for seeking this information) to uncover the truth.