A comment on your comment to matatudeity:

When I was a backsliding Protestant in Moscow, people kept assuming I was Catholic and it irked me to no end.

But it's undeniable that Protestantism comes out of Catholicism. It's a reaction to and a rejection of the errors of Catholicism, especially the high medieval variety. So Catholics and Protestants often debate the same issue, taking the opposite sides of the same argument. Orthodox, however, simply have different discussions.

For example the Pope of Rome: Protestants used to be under the Roman Pope and now they aren't. Catholics used to be and still are. Orthodox never were and still aren't. So "Pope or no Pope?" is an irrelevant discussion to us. We have a pope in Alexandria, patriarchs in Jerusalem, Antioch, Constantinople, Belgrade, Sofia, Tblisi, and Moscow, as well as several archbishops and metropolitans of independent churches and more than a thousand diocesan bishops all who are to their own flocks as the Roman Pope is to the entire Catholic Church (minus things like papal infallibility). So we're neither the minutely-organized monolith of Catholicism nor the anti-organization clutter of Protestantism. We're a different beast entirely.

And so forth. Protestantism often defines itself as a reaction to Catholicism; it was certainly born that way. Protestantism and Catholicism can be seen as two sides of the same coin. Orthodoxy is an entirely different coin (which has only one side or something. Not a great metaphor).

To a Protestant far removed from any other church, Catholicism and Orthodoxy can appear nearly identical (every good Russian would be outraged by this notion). To an Orthodox Christian far removed from any other church, the distinction between Protestants and Catholics is blurred indeed (and every good American is outraged by this notion).

The arrogant nose-stuck-in-the-air explanation of this is that after the Catholic church fell into error and broke off from the true church, it just kept splintering and splintering and splintering, and Protestant sects are all those splinters. Not a view I disagree with entirely.