Mercenaries have no place in your company and your culture. Doubters are a bit different. You certainly don’t want to create a culture of “yes maam” in your company. So some doubting is healthy. But it should be out in the open. The doubts should be expressed upfront and they should be discussed and debated. But once the decisions have been made, everyone needs to get behind them. Ongoing doubting is not helpful to a culture.