How many times have you received an e-mail, read it, then acted, only to find that the real message was in the 'trail' of e-mails below the one you read; below the 'fold' in web design parlance.
I usually browse through the trail to see if there's anything there for me, but last week, I didn't. The request seemed to be self-explanatory and self-contained. The trail below it also seemed to be giving various positions, so the author I read had assumed that a reader would work out from the complex trail what they were asked to do.
Not so, too many choices, too many assumptions would have to be made.
To convert this melange to communication, if you must send an e-mail trail, copy, paste and edit to make sure you send the message you want action on. Projects are too complex to think that a reader can work out what you mean from a long trail of e-mails from different authors full of discussion, fact, and inquiry.