"And so, with all the choirs of angels in heaven we join in their unending hymn of praise."
This person highlighted that which I'd been monotonously glossing over for the last 27 years of my life. In our response, the Holy, Holy, Holy, we are joining in with all the angels of Heaven because they are ALWAYS giving praise to God. As Newton so brilliantly wrote for a verse in his Amazing Grace, "When we've been there ten thousand years, bright shining as the sun; we've no less days to sing God's praise than when we first begun!"
In other words, time is non-existant. It means nothing as all praise is continuous. During the Mass, we just enter into this timeless loop of praise to give thanks and glory to God the Father through His Son, Jesus, in union with the Holy Spirit. That's why the Mass is the same Mass regardless of when / where it occurs.
Jesus died once for us on Calvary, and each subsequent "remembrance" of that sacrifice is a repackaging of His Sacrifice so that all may take part in His Salvation. At Consecration, we are witnesses to Christ's Death and Resurrection. The Body and Blood are separate, which is the physical sign of His Death. When the priest drops a piece of the now Consecrated Host into the now Consecrated Wine (His True Body and Blood), we bear witness to His Resurrection (keep your eyes peeled - this happens at every Mass!). Accepting the Eucharist is accepting the Divine Body of our Risen Lord, and to understand that this praise and thanksgiving is continuous is a mystery that never hit home until this wonderful man pointed it out to me.
So when I was at Mass for the Solemnity, I was blessed to remember this little Eureka moment, and when the time came to sing the Holy, Holy, Holy, I closed my eyes and asked that I be transported to Heaven to offer my singing in union with theirs. My heart was so full of love and praise that I was sure I'd burst. I didn't, luckily, so I was able to participate in the Eucharist. Ha ha! What a wonderful moment that was. It was a kiss from Heaven! I hope to always keep that knowledge within my heart during the Mass.