To protect yourself from sending messages too hastily, you can add a final confirmation, which you can of course make as elaborate as you wish.
(add-hook 'message-send-hook (lambda () (unless (yes-or-no-p "Sure you want to send this?") (signal 'quit nil))))
Another option is to simply set message-confirm-send
to
non-nil
so the question “Send message?” is asked for confirmation.