What is the subject line for this email?

Please respond to I have done a crappy job of being a witness and a friend. You are correct, and rightly so about the way I have patronized you. It has not been a conscious effort, but I understand your perspective and as I look at me, I am forced to admit you are correct. Christian hypocrites are a dime a dozen, and I am ashamed that I have fallen far short of what He has called me to be. I am very thankful for your business over that last 3 years. I know that my success here has been largely because of your help and business and I and my family thank you for it.
An Apology