In a moment of nerve, or perhaps bravery, I recently asked my local hasidic Rabbi the following question, "Why is your liturgy (ie: Nusach Sefard) such a mess? The grammar, in places, is rediculous, and you have brackets all over the place. What's up with that"
To my surprise he gave an excellent answer (I can't write the way that he speaks, so nothing that follows is verbatum):
"There is no one Nusach Sefard," he said. "At the begining of the Hasidic Movement, each Rebbe interpreted the liturgy (ie: the Nusach Ari) in his own way, with his own gloss, and produced his own nusach. Each was a little different from the other. Years later, when the siddur was printed, the editor tried to combine all the different variations. The result was the mess we have today. However, any Hassid who davens with a mesorah knows what to say, and what not to say. He uses the printed siddur only as a guide. Anyone who just says everything thats printed there doesn't really know what he's doing."
"And you know what else is interesting? Every Rebbe has a ruling which claims that his way of davening is the right way. Lubovitch, Satmar, whoever. They all argue that their way is right to the exclusion of all others, and that you can switch in to their way of praying, but you can't switch out. [DB: Rav Moshe has a famous ruling about Nusach Ashkenaz in which he says the same thing.]"
"It's amazing," my LHR concluded,"how their objectivity just disappears."