The send button is a design problem
An irreversible action with no undo, pressed while tired, on the thing you care most about. No wonder everyone has a story.
How to end an issue
Openings get all the advice. The last hundred words are what decides whether anyone replies, forwards, or opens the next one.
Why anyone still starts a newsletter
Email is the last channel where nobody else decides who sees your work. That is the whole pitch, and it is enough.