Very few email clients support that feature, or default it to off.
You can set up a header to mark messages with a read receipt, but Mail does not respond to them.
http://email.about.com/od/macosxmailtips/qt/et_request_recp.htm
It would be simpler to set up a default signature that stated,
"While I realize that when or if you read this email is none of my business, my life would be incomplete if you didn't respond immediately upon receipt of this email."
If your recipients are anything like me, your emails would just go straight to the trash after receiving either of those from you.