If the reply is angry, sleep on it. If it’s still true in the morning, send the calm version.

Waiting is not the same as backing down. What changes overnight is the proportion, not the facts, and the version that survives until morning is the one with the actual point in it. Sometimes you wake up and it no longer needs sending. Sometimes it still does, and now it is a sentence instead of a spiral.

Draft it tonight and set the rule that nothing goes out before breakfast. Read it once in daylight, cut the two hottest lines, and send what is left.