Most of them don't read your entire message. This is just the reality of our world and I've long since given up on any feelings I have on the matter. What's left is to structure my messages accordingly.
I write e-mail in layers.
If they don't read past the Subject line, what do I want them to know?
If they only read the first sentence, what do I want them to know?
If they only read the first paragraph, what do I want them to know?
And after the first paragraph, I go into detail. But at that point, it's actually a reference for myself. I'm prepared to have to say it or write it again in smaller chunks. I crack all the jokes about it that I can. Because, see, it is for my own health. =)
I'm always elated when, on the off chance, they do read carefully to the end. I've taken to embedding little funny turn of phrases or something funny, just as a Thank You to those who do. =)