Why are we so scared?

Say you're in the elevator with three other people. Two people, who are on one side of the Vader, find their floor and exit. Then, you'll always find that awkward moment when the other two remain - on the same side. One of the two always feels the need for symmetrical space and saunters on over. Why do we do this? Can't two people remain together? As one? Why do we have to recreate Vietnam?