Martin Lomasney created a famous saying on the importance of discretion:
“Never write if you can speak; never speak if you can nod; never nod if you can wink.”
At the time of Lomasney, it was not email but telegrams that were the principal method of electronic communication. But those telegrams just ended up on pieces of paper.
This was also the time before e-discovery. Now every email is subject to ending up in a lawyer’s hand during a law suit.
Think before you hit that send button. Maybe a phone conversation will be better. Or a nod.