Memory can preserve a tone after the actual words have gone.

What lasts is rarely the sentence. Years later you may have no idea what was said and still know exactly how it was said, whether warm, dismissive, careful or amused. Tone is stored somewhere deeper than content, which is why an old exchange can still affect you with no transcript attached. It also means the way you say something now will outlive what you actually said.

Assume the manner of your words is the part that gets kept, and spend a little more care there. And where an old tone still lands on you, naming it as tone rather than fact can loosen its authority.