Good question EFW.
The person performing the sacrifice has to possess the authority to do so through Apostolic Succession otherwise it's just crackers and grape squeezings. Simplified, the church had to be founded by one of the Apostles. So IIRC, that's RC, Orthodox, Maronite, Coptic, and probably a couple more I'm forgetting.
So I went to church all those times for nothing? Damn, now I'm even more pissed about it!
