A brilliant post from the brilliant Msgr. Charles Pope, at the Archdiocese of Washington’s blog on the superiority of ad orientem worship (emphasis in the original):
Indeed, we have the strange modern concept of the “closed circle” in so many modern conceptions of the Mass. Too often we are tediously self-referential and anthropocentric. So much of modern liturgy includes long lists of congratulatory references, both done by, but also expected of the celebrant.
Instead of the Liturgy being upwardly focused to God and outwardly toward the mission of the Church (to make disciples of all the nations), we tend today to “gather” and hunker down in rather closed circles looking at each other, and speaking at great length about ourselves.
We have even enshrined this architecturally in our modern circular and fan shaped churches that facilitate us looking at each other, and focusing inwardly, not up or put. The author Thomas Day once described Modern Catholic Liturgy as, “the aware, gathered community celebrating itself.” 
In the ancient orientation or “stance” of the Mass that was ubiquitous until 1965, the focus was outward and upward. Though disparaged by many in recent decades as the priest “having his back to the people” even this description shows the self obsession of the modern age. And to those speak this way about the liturgical orientation of almost 2,000 years, the answer must come, “The priest does not have his back to you. Actually it is not about you at all. The liturgy is about God. And the priest, and all the faithful are turned outward and upward to God.”
“Tediously self-referential and anthropocentric” describes about as perfectly as possible the source of my own annoyance and alienation at the narcissistic horizontality of the typical modern Mass. Enough with it!