Agree - the communal action that makes present Christ.

From the documents:

The Church is never more authentically and visibly "Church" than at Eucharist because the eucharist "is the outstanding means whereby the faithful may express in their lives, and manifest to others, the mystery of Christ and the real nature of the true Church." (Constitution on the Liturgy, 2)

Ten Things You Can Learn About Eucharist - http://www.tomrichstatter.org/eEucharist/e41theol.htm#Ten Things I Learned About The Mass

Connects Eucharist and Initiation (VII change to Trent)
Eucharist is Holy Thursday, Good Friday, and Easter
It is a sacrifice because it is a meal
Eucharist is a VERB - not a noun
Emmaus is the model for all sacraments - gathering, story telling, sharing, mission
Real Presence is experienced in many ways - present in scripture, gathered community, eucharist, misson
It is about UNITY  (why two forms/one rite is wrong)
Eucharistic Prayer is our common creed
It is sacrament of reconciliation