the potential energy of a body,is the work done by a conservative force on that body

the conservative forces are non dissipative,so it gets stored as potential



whereas the non conservative forces are dissipative,their work done is lost as heat etc!

as in friction,whic produces heat,causes wear and tear!



may b thats the reason!

 I think

   The change in potential energy of a system depends upon conservative force while the change in potential energy depends on intial and final positions.now conservative force is that force which depends only on initial and final positions not on the path taken.So the both things r related due to the intial and final position.  

The very concept of PE hinges on the existence of a conservative force. Only for conservative force does the idea of PE exist. For any two points in space the work done by conservative force is found to be the same always. This is assumed to be the decrement of a quantity we call PE.

For a non conservative force, the work done between two points will depend on the path and hence it can't be uniquely associated with the decrement of  any quantity.