The Trinity Again?

When a laymen begins their studies of the Trinity, church father Augustine made a helpful saying that comes to mind. “anyone who denies the Trinity is in danger of losing her salvation, but anyone who tries to understand the Trinity is in danger of losing her mind.”
There are good reasons for the complexity of questions and at times the absurd conclusions in place of the doctrine of the Trinity. Ultimately it is often confusing to me how some get this concept so wrong when it is so clearly implied in Scripture and in our face (literally) when it comes to the Incarnation.
The common error the heretics make against the Trinity is to observe it wasn’t in full blown form till it was spelled out in the fourth century at two great ecumenical councils (Nicea 325 and Constantinople 381). What the non-believer doesn’t realize is that many doctrines didn’t have to be refined till heresy came about and the early church father were constantly exegeting Scripture to combat and refute heretical claims. So while we don’t really struggle with the fact that Jesus was a man who walked in the flesh, first century skeptics did. And while we don’t argue over the canonicity of pseudopigrapha texts the early church did.
When people are shocked to hear that people today call themselves Christian but don’t hold to the doctrine of the Trinity, they should understand ultimately that this isn’t anything new at all. It is only something old wearing a new hat. Trinitarian doctrine needs to be instilled constantly in our services and in our preaching. Our preaching ought to make people think on the Trinity weekly if not daily.