I think I may have to remove my post/question as no-one is really "getting" what I'm saying. It is simply this: for those who KNOW their recipients don't require a subject line when recieving emails from certain people, there ought to be a toggle switch
to turn this function on or off.
For the record: I took English composition in college and have read Strunk & White's "Elements of Style," and - for business correspondence - I understand the necessity of a more formal approach. I indeed use this formal approach in ALL my professional dealings.
But, as I mentioned in the post just prior to this:
I am writing to my mother and father and my sisters and friends (who live far away) every few days, and my boyfriend, all of whom know me quite well. I don't think that writing quick notes to them requires adhering to the same parameters as business correspondence.
If my close relatives get an email from me but don't want to hear what I have to say simply because it wasn't prefaced with a subject line, then I have bigger problems than e-mail etiquette.