Push with respect, and under the assumption that the other person is probably doing the right thing. But push anyway. And never hold back. - Patrick Lencioni

What is most important is that team members get comfortable letting their colleagues see them for who they are. No pretension. No positioning.

The enemy of accountability is ambiguity

Team Number One The only way for a leader to establish this collective mentality on a team is by ensuring that all members place a higher priority on the team they're a member of than the team they lead in their departments. A good way to go about this is simply to ask them which team is their first priority. I've found that many well-intentioned executives will admit that in spite of their commitment to the team that they're a member of, the team they lead is their first priority. They'll point out that they hired their direct reports, they sit near them and spend more time with them every day, and they enjoy being the leader of that team. Moreover, they feel a sense of loyalty to the people they manage, and feel that those people want and need their protection. This is absolutely natural, common, and understandable. And dangerous.