Sometimes when certain Protestant Christians want to bait Roman Catholics (or other sacramentally-minded Christians, they accuse sacramental theology of being "magic." They are not kind people who do this, because I think you will understand it's the rough equivalent of being told that your momma visits Canaanite temples (But she's not even Episcopalian!). It's a short below the belt because a) its flagrantly ignorant and b) assumes faithlessness, even idolatry, of the person being asked.
Does everyone know the difference between "magic" and sacramental theology?
Magic is the manipulation of supernatural forces or mystical power through the performance of particularly engineered actions or prayers. Through these incantations, such powers are summoned and manipulated for the purposes of the summoner. Everybody probably has a good notion of this.
The way I like to explain a sacramental rite of the Church is as follows (with thanks to John Colwell): God makes a promise to his Church regarding his saving and healing presence among them. There are actions within the economy of salvation that the triune God wishes to perform among his people, and bids us pray to this effect. Therefore to pray for those very gifts is not presumption. The presence of the triune god is mediated by the Holy Spirit through the instrument of the Church's own prayers, the liturgy. The liturgy is the invocation of the divine promise, during which the Church begs him to be present in power and in healing. This is a question of grace, by which God offers a mystical and material salvation to a people who are themselves both mystical and material.
In these terms, one remembers that in John 6, Jesus teaches us that we need to eat his flesh and drink his blood - since we need it, we can only hope that it will be possible. We trust - not presume, because it is a matter of his own gracious promise - that he will give us this food and drink. In response to Him, we pray that we would be given it. We trust also that he does indeed give it to us. The action of the Eucharistic liturgy is both his and ours: his mediation of presence, and our reception of it as Christ's Church.
Sacramental rites are the concrete practices of reception of God's promises and therefore we consider them an enactment of salvation. God's activity is not limited to his promises and the economy of salvation that this entails, but it is normal.
The bottom line is that in the Eucharistic prayer, we beg for Jesus to come to us in a particular way according to his own promise. If we are not doing that, discussions about sacramental theology and the practice of the actual rites lose any Christian sense.
My other considerations of the Eucharist can be found here.