I read a post today (I think it was from Fast Company but I can't find the link) that said to write email that will be read, keep it short and to the point. No explanations, no niceties. Just give the reader one reason to keep reading and another to respond.
At the same time, I have been experimenting with images for social media. I looked at all the quotations floating across my feeds, and decided to make some of my own with words taken from the book I will be releasing this spring (still hoping that spring is actually on the way). Here's a sample:
I think the concept comes from an Aesop's fable. While it didn't occur to me when I wrote it (and it didn't occur to my editor), there is a fable about a fox and some grapes that are just out of reach. I just checked, and that fox walked away. The grapes must have been a little too far out of reach to keep him engaged.
The idea of reaching for an apple has history (you remember Eve and the serpent?). The idea that something just out of reach is more engaging than something we can easily reach also has history (it's the theme of half of the romance stories in books and movies). Everyone knows something about reaching for a shiny ripe apple.
Simplicity works best when it is only simple on the surface. An image (in words or in a picture) sticks because some part of it is familiar.
I suspect the same thing is true of abrupt emails that get results. It's not the length that is key. It's the ability to suggest something with a few words that already has some history and some staying power.