Something I already knew became suddenly clear today : the product or product pieces in the WBS and the relation to the activities. Although I already knew for a long time that it is good practice to make the WBS deliverable oriented instead of activity oriented it remained always a gradient where activities blended seamlessly in deliverables.
The key was that I used a mental trick derived from ‘Getting Things Done’, which says that you must write your activities action oriented, with a verb, active voice, i.e. do something. I was rephrasing the activities this way (more bang per spreadsheet cell).
Now I applied this reasoning to the WBS work packages, but I rewrote it as things, or part of things. Again the clarity improved considerably and wordiness got down. And then : klabammm…. flash of light : activities were clearly separated from the WBS work packages, the grey area between them was gone!!!.
I am quite sure if I read my PM books again I will find this trick in every single one, but I had to “invent” it myself before I understood and felt it, instead of just knowing it.