Project Managers are generally encouraged to be persistent and this characteristic is normally seen to be a “good” thing and something to be encouraged.
Consider the case of a Project Manager who has a preconceived agenda & seeks to impose it on a meeker member of the team. Despite the initial objections of the Team member the Project Manager persists and “badgers” the other into doing what She wants.
Six months later the project hits a major hurdle and the Project Manager realizes this was exactly what She was warned about all those months ago but chose to ignore in order to bash ahead with her agenda.
The wise Project Manager always listens to her Team and is prepared to question her own agenda with as open a mind as possible.
Persistence is a great attribute of any Project Manager but not when it impedes good judgement.