All emails should be 2 lines only, is something I learned when I started working in an office. For example,

  WHAT YOU ARE SAYING

  WHAT YOU NEED FROM YOUR AUDIENCE (RESPONSE OR DECISION OR ACTION ETC)

My boss taught me this. Because people just don't read long emails. Simple as. Do YOU (want to or have time to) read someone else's long emails?

As time goes on, often I say (to myself) "forget that", and write all the detail that is needed anyway, even in email. But only for audiences that may care about the detail (or otherwise are safe to skip the email altogether).

But who uses email at work anymore, anyway, right? I guess some organizations.