"But the natural man receiveth not the things of the Spirit of God: for they are foolishness unto him: neither can he know them, because they are spiritually discerned." 1 Cor. 2:14.
For example, believing that Mary was sinless, as the dogma of the “Immaculate Conception” states. Whether I accept this or not has no bearing on my salvation according to Scripture. Yet it is one of only a few extra-Biblical “ex-cathedra” doctrines proclaimed by the Magesterium that they say one MUST believe or be excommunicated, and therefor, condemned to hell.
I have come to believe that arguing issues other than what is required to be saved is pointless and used by Satan as a distraction from the main issue which is, “What must I do to be saved?”. "Believe on the Lord Jesus Christ" is the answer, and until that sinks in and becomes real in a person's life and they are indwelt by God's Holy Spirit, no other things of God can ever make sense.