Continuing what tsl said, you (or whoever built the bike) will want to grab a whole bunch of brake and exposed dérailleur cable and give it a good squeeze or tug to make sure everything is seated as much as possible before it goes out the door the first time.

Though I have to say, in the days when steel was real, using Campy cables and housing, bits, seemed to result in the least amount of slop after the above exercise. Must have been tighter tolerances between the interfaces.