The best laid schemes of mice and men go often askew..

In his book The Fifth Discipline, author Peter Senge describes five learning disciplines that promote excellence in the organization (2006):

1.    Personal mastery - learning becomes the foundation on which innovation and creativity may be built.

2.    Mental models - Mental models are constructs that we create in order to explain occurrences in our world.  These models directly affect the way that we experience the world around us. 

3.    Building shared vision - Shared vision promotes creativity and risk taking because it compels people to innovate.  The strength of the vision and the extent to which others adopt it depends on the “enrollment” of the people who participate.

4.    Team learning - Team learning occurs when a team is able to operate as a unit larger than the sum of its parts. 

5.    Systems thinking - No longer operating as individuals, the team has reached a collaborative state where the sum is greater than its parts; the team is able to function on a higher level and create products, services, or innovations beyond those which could have been made alone.

From my perspective as a project manager, I must seek out and remove impediments which prevent our team from succeeding.  These impediments can be directly tied to project deliverables, such as lack of resources or implementation problems, or they can be related to the system in which we work.  That is, if the team is able to overcome the limitations of individual work and become a true team as described by Senge, I believe that we can handle any block that we encounter.

Planning is the act of creating a scenario in which things go a certain way.  For example, I can create a project plan that says "we will build product X in 6 months at this pace, with these building blocks, for this amount of money."  However, it is in the support, training, and efficacy of the team that this plan comes to pass.  I can identify risks and make a plan to mitigate them, but if the team doesn't react well to the risk's occurrence, my plan may be useless.  If they are able to react as a cohesive unit, helping one another succeed, then the plan is able to be carried out.

As a project manager, I strive for control.  But I must also acknowledge that control is an illusion and that flexibility, innovation, improvisation, communication, and team work are worth more than any plan I could write.  A stack of paper saying how things will work will always lose out to the reality that we experience when we embark on a new project.  The wise project manager knows this, and embraces it.
 
References

Burns, R. (1785).  "To a Mouse, on Turning Her Up in Her Nest with the Plough."  Retrieved from http://en.wikipedia.org/wiki/To_a_Mouse

Senge, P.  M. (2006).  The fifth discipline (Revised edition).  New York, NY:  Doubleday, Inc.