Have you ever had the opportunity to attend Mass in the Ordinary Form where the liturgical music first and foremost followed the first directives in the GIRM? In other words, have you ever been to Mass where plainchant (in Latin and/or English) was generously employed, the Propers were sung, the priest would chant most of his parts so the people could also enter into the dialogue with sung responses and if, IF there was time, a small, highly competent schola would sing a motet or two? If you have, did you find that there was an ethereal quality to the liturgy that directed all of your attention to what was going on at the altar in the sanctuary? Did it imbue you with a sense of the other-wordly, the supernatural, the realm of angels, heaven itself? Did it raise your mind and heart to things of God such that you left Mass with a renewed energy to bring Christ to the world?
I feel sorry for you.
I assume, then, that you have experienced what most American Catholics do...the "standard" (or shall I say "sub-standard" if I want to be a bit uncharitable and refer to the quality of the music) liturgy where a large, mostly untrained choir (led by a cantor at a separate microphone) sings (or in some cases, belts) a "four-hymn sandwich" in between all those speaking parts. At these liturgies, the congregation is asked and sometimes cajoled into joining in singing such and such which is number blah, blah, blah in the disposable hymnal (unless the parish is lucky enough to have permanent hymnals that will be replaced every five years as to take advantage of all the wonderful and new songs just published...ooh, be still my excited heart!). At these parishes there are people employed as directors of music (and liturgy in many cases) who have NO idea what a Proper, Ordinary, Graduale, are and most likely have, at the very minimum, NEVER EVEN READ the General Instructions to the Roman Missal which enlightens us to what we should be doing at Mass. I'll admit, you may have actually sung some beautiful songs that have rich harmonies, deep theology in the lyric, and fairly easy to sing melodies. But, more than likely, the music you sing at Mass was written AFTER 1980. Oh, snap...did you catch that? I said "the music you sing AT Mass"?
The last time I checked, and I'm pretty sure that this is still the case, we aren't just hypothetically, in a perfect world, to just sing music at Mass as the primary form of worship. Liturgy is a public work of the people to corporately and individually worship our Lord. Liturgical music, as simply one piece of the worship experience, should actually do something other than just give us something to do. It's supposed to allow us to fully enter into the prayer by either accompanying a liturgical action (the Introit aka "The Entrance Hymn", the Communion Proper otherwise known as the "Communion Song", etc.) or by being the liturgical action itself (the Eucharistic acclamations, the Responsorial Psalm). When the powers that be stop trying to control the congregation's level of participation by forcing them to make and eat the stacked, plain (unless there's mustard) four-ham...uh...I mean the four-hymn sandwich, and give them the beautiful opportunity to express their prayer in song in the wise way mother Church has devised (through the sung Propers and Ordinaries and beautiful hymns), we will see a rise in holiness in the congregants. I mean, what a better way to see what "active participation" looks like than to elevate the prayer and worship experience to a point where souls, beautified by the work, receive Christ in the Word and Eucharist and then take Him outside of the church building and bring Him to the rest of the world. (Oh, and by the way, for whatever reason, music holds an amazing power over us...it penetrates the body and goes straight to the soul...giving liturgical musicians an even greater responsibility to make sure that the music that is sung at Mass is, as St. Pius X commanded, holy, universal and true art. If music has the ability to teach us the Faith even if we don't recognize that we are being educated then it is absolutely paramount that we follow the magisterial directive that the liturgical music be holy, universal and true art).
I believe that if liturgical musicians just eliminate the "four-hymn-sandwich" approach to planning music for Mass and instead give what the Magisterium recommends a chance (Propers, Ordinaries, hymns that are holy, universal and true art), we actually might see a shift in how we pray and live as a Catholic people. Lex orandi, lex credendi, lex vivendi, after all.