People generally think of tension as a bad thing.  An engineer, however, would have a more positive view of how to use tension to create structure.  Bones for example grow along lines of Stress. 

The diagram below suggests that vision creates tension between the current reality and a desired future.

The vision or goal creates tension between the real and the ideal.  Here, tension acts like an elastic band and as we know, tension seeks to resolve itself.  Either current reality will align itself with the vision or the vision will resolve itself in favour if current reality.