What project manager don't like to hear is how work is really done. Work is...
What project manager don't like to hear is how work is really done. Work is many, many small tasks. If a project manager wants to know what is going on you must not tell them about the small tasks. They will order you to not do the small task, only the big tasks. In their mind, large tasks are not made of small tasks and in mentioning the small tasks you insult their rank in the organization. The small tasks must be done in secret, to protect the feelings of the project managers.
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For example, checking to see if we are using pound-force-seconds or newton-seconds is a small task. Both scale with total impulse, so it should be fine. Project managers at NASA correctly made sure their staff didn't focus on small things, or else they'd never get to Mars and project managers would have to report up the chain of command that their staff was busy doing small tasks.