So I noticed that when you send an email (I have the standard Mac "Mail" application-- you know, the one with the postage stamp with the eagle on it?) without a subject but with text in the body of the message, it asks you if you're sure you want to send it because it has no subject.
BUT when you send an email with just a subject and no body, it doesn't alert you.
Isn't this odd? You'd think the body test would be more important to remember than the subject. Guess not!