Silence. Does God really mind a bit of noise? Can't he handle the banter of socialization in His house?
We need silence in the nave and sanctuary of the church, especially prior to Mass. He can handle the confusion and clatter of people exchanging hellos. We need silence not because God is weak, but because we are.
From the GIRM: 45. Sacred silence also, as part of the celebration, is to be observed at the designated times. Its purpose, however, depends on the time it occurs in each part of the celebration. Thus within the Act of Penitence and again after the invitation to pray, all recollect themselves; but at the conclusion of a reading or the homily, all meditate briefly on what they have heard; then after Communion, they praise and pray to God in their hearts.
Even before the celebration itself, it is commendable that silence to be observed in the church, in the sacristy, in the vesting room, and in adjacent areas, so that all may dispose themselves to carry out the sacred action in a devout and fitting manner.