Certain roles have to be filled for an extreme team to work—programmer, customer, coach, tracker.
A sports team works best when there are certain roles that someone takes responsibility for. In soccer you have the goalie, the striker, the sweeper, and so on. In basketball you have a point guard, a center, a shooting guard, and so on.
A player taking one of these positions accepts a certain set of responsibilities—setting up teammates for scoring, preventing the other team from scoring, perhaps managing a certain portion of the field. Some of the roles are nearly solitary. Others require that the player correct the mistakes of teammates, or manage their interactions.
These roles become customary, and sometimes even embedded ...