Good colleagues can still collide when ownership is vague. Two people can both have useful context, strong taste, and enough experience to be dangerous. Without clear decision rights, a technical disagreement can quietly become a status negotiation.
That is why the org chart matters even in healthy teams. Not as theatre, and not as a way to shut down ideas, but as an API for direction. Who decides? Who advises? Who must be consulted? Who owns the tradeoff after the meeting ends?
Professionalism is not sharing every thought with every colleague at every moment. It is knowing which context helps, which context distracts, and where a disagreement belongs. Clarity of hierarchy is not the enemy of collaboration. Often, it is what lets collaboration survive contact with real decisions.