In an argument, a few seconds of silence lets the real point catch up to the loud one.

The first thing you want to say in a disagreement is almost never the important thing. It is the fastest thing, which is a different quality entirely, and it is usually about winning the exchange rather than about what is actually bothering you. The real point is slower and arrives a few seconds behind.

Practise leaving a gap before you answer, particularly when you feel most ready. Count to three. The silence is uncomfortable and it is doing work. What surfaces in that gap is generally closer to what you meant.