The Holy Mass is a prayer itself, even the highest prayer that exists. It is the Sacrifice dedicated by our Redeemer at the Cross, and repeated every day on the Altar. If you wish to hear Mass as it should be heard, you must follow with eye, heart, and mouth all that happens at the Altar. Further, you must pray with the Priest the holy words said by him in the Name of Christ and which Christ says by him. You have to associate your heart with the holy feelings which are contained in these words and in this manner you ought to follow all that happens on the Altar. When acting in this way you have prayed the Holy Mass.
Don’t pray at Holy Mass, but pray the Holy Mass.
—Pope Saint Pius X
[pg 833 of the 1962 Missal (?)]