The traditional Catholic definition of a sacrament is "an outward sign of inward grace, instituted by God [though more likely, I think, by god-seeking men] for our sanctification." As ever-wordy Thomas Aquinas explains more fully: "It is the nature of man to be led by things corporeal and sense-perceptible to things spiritual and intelligible."
In other words, rites, rituals, ceremonies involving symbolic actions, liturgical language, beautiful music, bells and smells--such hocus pocus, when conducted solemnly and reverently by and for "believers", can confer upon participants a kind of edification--both spiritual and psychological--that connects them with a transcendent (and not really explainable) power.
Hence, the Mass--Western man's most admirable and magnificent congeries of sacramental mumbo-jumbo. Vatican II fussed about trying to make the Mass "accessible" by translating it into vernacular languages. Truthfully though, there was no real need. Indeed, the very foreignness of Latin probably contributed to the overall theatrical and mystical effect. Remember: sacraments are not "how to" instruction manuals--each corporeal "appeal to the senses" does not need to be intellectually analyzed. Rather, it is the overall metaphor that must be perceived, embraced and, ultimately, assimilated into the believer's very being. At the Mass, the devout are swept up in the majesty of the EXPERIENCE--knowing that such and such a prayer (who cares if you understand the words?) points to such and such a meaning, knowing that such and such a stylized gesture signifies such and such a transcendent truth, knowing that such and such a sight, sound or smell directs us to ponder such and such a communal commitment or social contract.
And thus, when the whole story of Jesus' passion has been symbolically reenacted and made "sense-perceptible," the believer reaches the climax of his experience: he unites himself with the story he has experienced--he eats and drinks his god and in so doing becomes godlike himself. This union with the god is also a union with all other communicants. And it is, above all, a reaffirmation and celebration of the very selfhood/godhood of the participant. It is "grace."
Now, in discussing the Mass, I have used terms that might be considered pejorative: hocus pocus, mumbo jumbo, theater, choreography. I have done so because, to an outsider--even to a Protestant--such an elaborate ceremony, full of complicated maneuvers and mysterious language, may seem like nothing more than a ridiculous vaudeville routine or an absurd Ionesco farce.
Still, don't get me wrong. Though I have little love for asinine and inhumane Catholic dogma, and though I can muster almost no respect for the Pope and the hierarchy, I DO care deeply about the Mass. Because I am an initiate: I "get it" and, whenever I participate, I "get something out of it." Call it grace. As far as I'm concerned, doctrines and specious definitions of what actually "happens" (you know, all the transubstantiation prattle) matter not a whit and have no bearing whatsoever on the experience.
Oh, don't start nagging about my cognitive dissonance and my intellectual inconsistencies. I realize that trying to discuss mythological stuff in logical terms just doesn't work. In truth, my rational brain can make no sense at all of my emotional attachment to the Mass. And, as I've said elsewhere in this blog, I am convinced that it's pointless to try to understand, in human language, those necessarily fuzzy concepts we label "god" or "gods" or "ultimate reality." But so what! So what if the Mass IS just a vaudevillian delusion; at the very least, it is MY delusion and, as long as it continues to afford some small measure of grace to my rather haphazard life, I will cling to it. Sursum corda. And, to be sure, "Deo gratias."