It's my experience that most of my Catholic and Protestant friends don't care all that much about the finer points of theology. They look to their faith for strength to face the daily challenges of life. They often view their church as an extended family, where they have friends and feel comfortable, a home away from home. They believe in a real but generalized way. God. Jesus. Morality. Hope, Faith, Love. Maybe most of them don't know all that much about the distinctive dogmae of their particular churches - and they don't particularly care.
When it comes to, say, the Immaculate Conception, many Catholics (and Protestants, too, of course) confuse it with the Virgin Birth. (Many in both groups even have doubts about the Virgin Birth.) Transubstantiation? Most Catholics I know don't accept it as some sort of re-creation of the crucifixion. Representation, yes, but they do not believe that words by a priest actually propel a substantive change in the bread and wine. As for Protestants, they generally view both faith and works as important - just that Luther and Calvin rebelled against the popular medieval notion that certain prayers or other rituals stacked up 'brownie points' that got the believer closer to heaven. Etc.
There are hardcore Christians who make a lot out of the finer points of doctrine, but they are a small minority - fortunately. I just finished a book on the ancient church councils and all the competing factions, all the dirty politics involved, and what a mess.
Frankly, when I consider this vast universe, with maybe a billion stars - or even a billion solar system - most theological disputes, whether about predestination or the Assumption of the Virgin Mary, seem trivial. We live in such a marvelous, mammoth, majestic, miraculous and mysterious world that I am in constant awe, but also ready to confess both a deep skepticism about the details of theology and a deep and abiding faith in our amazing Creator God. I understand God through the example, teachings, and sacrifice of Christ, but am not sure that I am more favored in the eyes of the Almighty than faithful and compassionate Buddhists, Muslims, Hindus and those of other faiths.
Some years ago it was my privilege to spend awhile with an inspiring Hindu family in India. I decided then that if God doesn't find a place in heaven for them - well, my chances are pretty slim.
Let's make religion a bridge and not a barrier.