That's exactly my feelings about the Tridentine Rite. It has a very cold, distant, and sober feeling to it. While the rite may have been truncated version of various pre Reformation Western liturgies, it was definitely influenced by the dour, very Calvinist influences that crept into (Or where deliberately embraced) by the Vatican in order to combat Protestantism. The Byzantine rite, by contrast has a much warmer, and communal feeling to it that is really lacking in the old Tridentine rite. Whether sung with high operatic style music, or simple plain chant, this rite has a much more personal feeling to it worship and less of a "businesslike" style.
It is almost as if the RCC, in order to combat Protestantism and its dour doctrines of predestination and iconoclasm, chose to "fight fire with fire" and became more streamlined in liturgy and severe in theology/morality. I guess that this was felt to be the trend that Western Christendom was seen to be heading in (After centuries of a more folsky, populous Christianity having taken hold amongst the people). It's unfortunate because so much of the old, pre schism form of "Western Orthodox" Christianity was preserved in these old traditions and the Reformation era closed the coffin on them completely.
I'm so happy to have been raised in Italian Catholicism. Italy was, of course not touched by the Reformation and the atmosphere of Catholicism is still very folsky, more akin to the Medevil type then in those countries which were the battleground for the Reformation/Counter Reformation. I always felt that the Italians, even though Roman rite are probably (Still today even) closer to Orthodoxy in their interpretation of Christianity then are those Catholics in Northern Europe.
I've thought about this, too. Jansenism, somewhat a Calvinist Catholicism, though formally condemned, was influential in France and on the Irish. Perhaps this helped give the impression of a severe spirituality.
It's funny you mention that the northern countries were more rigid. I recently heard a joke that northern Russians are so stiff that you can hammer them into the ground.
I have Slovak and Hungarian background, and I do notice a difference in Catholic culture from where I'm at now (Irish & German concentration) and from the Catholic churches of my grandparents' town, which is more ethnic (Central & Eastern European) and "folksy"/friendly.