Sadly, that thought came to me today as I was witnessing the Mass unfold today where a friend's daughter was celebrating her first communion with maybe two dozen other kids. I say "witnessing" because, as my wife said so insightfully, participation was oddly missing. Everyone remains seated. To a Catholic, celebrating the Mass is odd when standing, kneeling and sitting at the right times is not there. The stark feeling of irreverence was driving me nuts, especially when the Word of God was being read (we should stand) and when the bread and wine were being consecrated (we should kneel!). I suppose it was only logical that the soloist sang in many parts of the Mass but no one sang the Hosanna. Or, as another friend at that same "Mass" said, he didn't even see the Host elevated when he announced that "this" (hidden within the circle of first communicants standing around the altar) was the Lamb of God.
Staying seated like that, it was like nothing more than being spectators of some show or movie. Yes, we sang, or spoke our replies, but each one of us is more than just a talking head. The entirety of each of us was created by the Father, redeemed by the Son and sanctified by the Holy Spirit. That includes our bodies. We are called to love our God with all our minds, hearts, soul and with all our strength. The entirety of our strength is not exclusively in any aspect of ours but in every aspect, and that includes our bodies.
There's this interesting relationship between smiling and happiness which applies, I think. When we are happy, we smile. It also turns out that smiling "tickles" our brain into feeling happier. Our bodily actions relate in the same way with our faith. St. James tells us that faith without works is dead precisely because it isn't a complete, living faith if it does not involve our complete, living selves. If our bodies do not work in accordance with what we believe, then we risk that same influence travelling down from a bodily laziness to worship to a rational laziness. Is it any wonder that many among us who stop worshipping in Church have also stopped believing the faith of their fathers? It's not just that the lack of works reveals a lack of faith, as the Evangelicals usually emphasize that works are fruits of our faith. St. James hits it on the head when he says that faith without works is dead, because one without the other is incomplete. One of my favorite authors/teachers relates that to either a body without a soul, which is a corpse, or a soul without a body, which is a ghost.
The Holy Spirit rightly calls that sort of worship "lip service".