• we have to give our supervisor our root passwd
• we can't lock our screens when we're away from our machine
• we are not allowed to encrypt any files on our system
• we have to agree that anything on our computers is owned by the company and they can access it
• no personal business on our computers

No problem... I simply ssh to another box where I do all my email. I don't give my work email address to people unless it will only be work related. Of course, with email, you can never assume it will always be secret.