What Tim said. The email isn't random, it allows the message thread to get recorded in NetSuite to the appropriate records. I resisted this initially, too, but it's really how you want emails to send -- especially when they are transactional. The "paper trail" is important if you have lots of people on your team who need the visibility. The Communication tab saves a lot of guess work and email threads "lost" in other peoples sent items / inboxes.