The biggest problem with emails is that they get swamped with them...good, and bad. I worked at an outfit that had hundreds of emails a day, and about one-third were legit. The rest were spam and junk! In a case like that make sure your subject line looks like business otherwise they may delete it because even with firewalls and everthing else some junk gets in once in a while.
They haven't got the time to sort through each and every one they get, so again, make your subject line look important.
Later