It is because of the intention of the Lord, and the reality of all the things that the Eucharistic celebration is that the council reaffirms yet again, the principles of participation:
The Church, therefore, earnestly desires that Christ’s faithful, when present at this mystery of faith, should not be there as strangers or silent spectators; on the contrary, through a good understanding of the rites and prayers they should take part in the sacred action conscious of what they are doing, with devotion and full collaboration. They should be instructed by God’s word and be nourished at the table of the Lord’s body; they should give thanks to God; by offering the Immaculate Victim, not only through the hands of the priest, but also with him, they should learn also to offer themselves; through Christ the Mediator (Cf. St. Cyril of Alexandria, Commentary on the Gospel of John, book XI, chap. XI-XII: Migne, Patrologia Graeca, 74, 557-564.), they should be drawn day by day into ever more perfect union with God and with each other, so that finally God may be all in all.
We are told that a liturgical literacy underscores their involvement in the Mass. This is an involvement of “conscious” action, devotion, and collaboration. The notion of sacrifice isn’t limited to the priest performing rituals in persona Christi. Vatican II reminds us of the expansion of the notion of sacrifice: that the laity bring themselves to offer. The end result being the ultimate union with God in heaven in which we presume our sacrifice, our act of worship, will be uncluttered and complete.