This letter lets a friend know that you feel taken advantage of.
1234, Main Street
Boston, MA 02123
07 April, 2005
<Recipient Address Goes Here>
I am sorry to have to write this letter, but there is something I simply must get off my chest. Do remember when you <friend's action>? Ever since then, I have felt used and offended by what you did. I really feel that you took advantage of our friendship.
I know that you aren't ordinarily the kind of person to do something like this, and maybe you had no idea that I'd take it this way, but I wanted to take a chance to discuss it with you and let you know how I feel. I certainly don't want to lose our friendship, but I know that if I continue to say nothing, what you did would eat away at me, and our friendship would die a slow and painful death.
I hope you'll call or write back and let me know your side of the story. Let's patch this misunderstanding up and get on with happier times. I'll be looking forward to hearing from you.
encl: <List of enclosed items goes here>