PARSONS: This guy is a dutiful member of the working class. Winston often sees him at lunch and his family lives near Winston. Parsons is really proud of his children who want to be Thought Police. He always brags about them. When they treat Winston as a criminal, I think it makes Winston a little weary of this man who is almost a friend to Winston. I think his character is put into this book to contrast Winston's character. He serves as what we call a foil. His duty to the country and pride is opposite of what we experience through Winston as Winston questions the government.

SYME: This man also appears to be a friend of Winston's. They too eat lunch together often. Winston's talks with Syme seem to be about the new versions of newspeak. Syme is committed as well to his job, but he was a thinker so Winston had Syme pegged from pretty early on. In book 1, chapter 5:

Unquestionably Syme will be vaporized, Winston thought again. He thought it with a kind of sadness, although well knowing that Syme despised him and slightly disliked him, and was fully capable of denouncing him for a thought criminal if he saw any reason for doing so. There was something subtly wrong with Syme. There was something he lacked: discretion, aloofness, a sort of saving stupidity.

I think Syme is type cast as a sort of Winston early on to show us what could happen to Winston eventually. Syme too is stuck between what he knows and being faithful to the government, but Winston here points out the average flaws Syme has that could and eventually do get him in trouble.

O'BRIEN: Depending on where you are in the book, Winston goes through varying stages of intrigue about O'Brien. Winston has an uncanny respect for O'Brien. He thinks O'Brien might be the key to the underground Brotherhood Winston may want to be a part of. I think this character's position in the book proves that Winston wants to believe in something greater than himself, and has hope to find it in another human. I don't want to give too much away about his character because there is a good surprise you'll learn in Book 3 about this character.