I never like to say that Regina Pacis "performs" at a Mass. That's not our function. If our music isn't integrated with the liturgy and doesn't help the congregation to be lifted toward God, we're there for the wrong reason. That's why I loathe being applauded at the end of Mass also; we're just ministers.
I should know. I, Paul, have led "worship" both privately and at Mass. While singing and playing guitar, I could sense when I was adopting something of a rock star mentality (when does Guitar Hero: Oregon Catholic Press come out?) and trying to steal the spotlight from God in the name of "worship" based solely on emotion. I did that as a lector also, over-dramatizing Scripture so that it was more the word of Paul (and not the one from Tarsus) than the Word of the Lord. These were tough but necessary lessons in humility for me.
With that in mind, I link to a great Chant Cafe post by Adam Wood about that viral video of a priest singing a song called "Hallelujah" by noted liturgist Leonard Cohen to a newly married couple in Ireland. I've seen reactions to it such as, "Wow, isn't this cool?" to "Pope Francis is making this possible." I'm not saying you can't admire the priest's singing ability, but Wood brings up a simple point: Whose wedding is it, anyway?
The first big problem is that the wedding liturgy is about the couple, not the priest. (It's about God, first. But, whatever, right?) The singing drew attention away from the couple and directed it toward the priest. This is selfish and narcissistic, and robbed the couple of what is rightfully there's [sic: sigh].
Priests tend to forget how a wedding functions in the life of the couple. For a priest - he may preside at hundreds or possibly thousands of weddings in his lifetime. A couple gets married only once. It doesn't matter if the priest is bored, or has heard all the prayers before, or has to do this same thing again tomorrow. Each wedding is a unique event in the life of a couple, and a priest should not impose his own personality onto that.It's important to remember that the priest merely officiates at the wedding in the Catholic rite. In his presence, the couple administers the sacrament to each other (CCC 1623).
We sing at a number of weddings, including one next month. At any Church function we're part of, may we simply add to what God is doing in our midst and not become the focus of the event.