It is very rare for anybody to be able to complete a productive activity in isolation.  We all need the cooperation of others at some point.  We can put up barriers to limit inter-action to inputs and outputs (e.g. to buy materials, retreat to a lonely cell to make a product then sell it through to a wholesaler) but it would be a static world, unable to progress and develop, if everyone worked in that way.  Not wanting to promote the cubicle world style of project management I firmly believe in the creation of effective teams to tackle all activities in the workplace.