This letter apologizes for behavior that may have been offensive to someone.
1234, Main Street
Boston, MA 02123
07 April, 2005
<Recipient Address Goes Here>
I am writing to apologize for my recent behavior. I realize now that what I did offended you and I am truly sorry for that. It was unforgivable of me to <behavior>, and I don't know what I was thinking. Indeed, I wasn't thinking and that was the problem! Had I stopped for a moment to consider your feelings, I would have seen how insensitive I was being and have stopped immediately.
I hope that you can forgive me for my rude behavior. Please know that I never intended to hurt you or cause you embarrassment. Indeed, I am now the one who is embarrassed. I hope that you will allow me to find a way to make it up to you. Again, I am deeply sorry.
encl: <List of enclosed items goes here>