Love, of course, that's a given. Mail, also. You can assume a couple of things right off the bat: effort, time, and some words. These are always put in the love mail mixture.
But what else goes into love mail?
Not a shred of humanity. Nor is any human emotion required to make love mail. Love mail could be created and published entirely by robots. Although, I don't think we've reached that kind of technological breakthrough, but wouldn't that be nice? It might save us some time, but it might nullify the "love" of "love mail."
What do we define love mail as?
It is all sorts of things. Love mail could be a "hello" from a friend, or a "good-bye" from an enemy. It's "see you soon" and "welcome back" simultaneously, it's music recommendations and homework help. Love mail doesn't have to be right or wrong or even true or even useful in the slightest sense to any whose eyes fall upon it. It is love mail simply by existing.
And so... this is love mail.
And you are its recipient.