Thomas Aquinas on Liturgy

Excerpts from a review found at New Liturgical Movement:

...Central to St. Thomas' liturgical theology is a theocentric focus – a theme discussed at length in the book. For Aquinas, everything within the liturgy is first and foremost oriented toward the worship and glorification of God – even the sanctification of man takes a back seat to this. In fact, our sanctification is itself directed toward the service of the rite, being our incorporation into the glorification of God through Christ, accomplished through the unbloody sacrifice offered in persona Christi by the priest. This sacrificial dimension of the liturgy, so often pushed aside in our modern day, is also highlighted by Berger, along with Thomas' sacramental theology.

The red-highlight is indirectly interesting vis-a-vis sacred music, as Pius X used the conjunction "and" between "glorification of God" [and] "sanctification of the Faithful" in describing the purposes of sacred music.

Be that as it may, think for a moment: does your Parish' Mass "glorify God?"

...The liturgy, by contrast, is the very practice and expression of the Church herself. You might say that this is the Church in her own voice. The liturgy then is an authoritative source by which to measure the truth of theological principles. Berger notes that Aquinas does such 57 times in the course of the Summa Theologiae.

Thus, "Cafeteria Liturgy" is a danger not only to the faith of the congregation, but a perversion of the Liturgy's purpose per se.