My trick is to start by adding “don’t send” in the BCC line of every email first thing. Then only remove it after writing and double checking everything.
If you try to send it before removing the “don’t send” text, Outlook will show a prompt that it doesn’t recognize the email address and will ask you to confirm before sending.
Genius, it’s like a tax on walking. If you could get anywhere by walking in America, these would be all over the place.