To be a member of the Catholic Church, in union with the Pope, the successor of Peter. When I’ve looked at other churches - primarily the Orthodox - it is the last bit of the Nicene Creed that keeps me Catholic. One, Holy, Catholic, and Apostolic. Lets give the benefit of the doubt on Holy to all churches, despite the sins and failings of their members. One, as in a single, unified group of believers - I don’t see this in any of the broadly Protestant or Reformed churches. Catholic - as in Universal - is where I think the Orthodox are lacking, as they are implicitely national/ethnic. Apostolic - granted from my Catholic perspective - would also preclude the reformed churches. I’m far more on the traditionalist side, so the past 12 years have been especially challenging, at the top levels, though the young clergy give me hope. Sorry, that was a bit long winded.