One of my takeaways from holding my tongue when I really want to say something is learning more about all the junk that bubbles up from the subconscious as its deterministic nature is formulating responses based on past experience and conditioning, some in agreement and some in disagreement.

In effect it's exactly like attending breath, noticing distracting thoughts arise and gently returning to breath. It's "witnessing" the conversation from a different perspective, a more real perspective, and analyzing one's own thoughts as dispassionately as the other's vocalization of their thoughts.

How many times do we feel so right about what we say in the moment, only to regret it later? How hard is it to own up to our own contribution or empathize with the other's contribution? It's even more challenging in the moment.

I'd say the most useful first tool in any spiritual path is one that brings about clarity of mind. One that concentrates a scattered mind. It's foundational.