The sad fact is most of us don't know that the Mass, especially on Sundays and Feast days, are supposed to be sung. The sung Mass (Missa in Cantu) remains the normative form in the Roman Rite – but regrettably, it is not the norm in most parishes.

- Constitution on Sacred Liturgy (1964).
For the celebration of the Eucharist with the people, especially on Sundays and feast days, a form of sung Mass (Missa in cantu) is to be preferred as much as possible, even several times on the same day.
- Musicam Sacram, 1967.
The Christian faithful who gather together as one to await the Lord’s coming are instructed by the Apostle Paul to sing together psalms, hymns, and spiritual songs (cf. Col 3:16).Singing is the sign of the heart’s joy (cf. Acts 2:46). Thus St. Augustine says rightly, “Singing is for one who loves.”[48] There is also the ancient proverb: “One who sings well prays twice.”
-GIRM #39