I think that the server's purpose in the Mass is to make sure the Mass itself, technically, will go as perfectly and smoothly as possible-- so that the priest will be able to perform his spiritual, priestly duties to the best of his abilities. This means having things there for the priest, ready to go, and having things tidy and organized. The server's purpose is also to make the priest look good (to put it bluntly). But mainly to make sure nothing gets in the way of the priest and his works, that being distractions (that's a biggy; cell phones, dripping candle wax, if his vestments are causing a problem, and so many that I won't waste your time in naming them all), and making sure everything is set to go as smoothly as possible. Not to mention being completely reverent as possible along with all of this.
With all of this being said, as a server, you have no time to meditate or think about what's happening right before you. I understand that this is part of being a server. You sacrifice yourself for the Mass. But that's why servers will obtain higher indulgences than lay people while attending Mass. Which means that server positions should not be thrown around to whomever.
All together, servers add a tremendous dignity and eliminate many errors and distractions from our divine worship. This is an essential part of the reverent offering of the sacrifice of the Holy Eucharist.