Letters of Note, a blog I came across in my internet travels, has a letter written by a freed slave to the man from whom he was freed. As someone pointed out online at the beginning of the letter you're thinking "this poor man had a serious case of Stockholm Syndrome and then by the end you realize he's written a letter infused with sarcasm:

To My Old Master, Colonel P.H. Anderson, Big Spring, Tennessee

Sir: I got your letter, and was glad to find that you had not forgotten Jourdon, and that you wanted me to come back and live with you again, promising to do better for me than anybody else can. I have often felt uneasy about you. I thought the Yankees would have hung you long before this, for harboring Rebs they found at your house. I suppose they never heard about your going to Colonel Martin's to kill the Union soldier that was left by his company in their stable. Although you shot at me twice before I left you, I did not want to hear of your being hurt, and am glad you are still living. It would do me good to go back to the dear old home again, and see Miss Mary and Miss Martha and Allen, Esther, Green, and Lee. Give my love to them all, and tell them I hope we will meet in the better world, if not in this. I would have gone back to see you all when I was working in the Nashville Hospital, but one of the neighbors told me that Henry intended to shoot me if he ever got a chance…

As to my freedom, which you say I can have, there is nothing to be gained on that score, as I got my free papers in 1864 from the Provost-Marshal-General of the Department of Nashville. Mandy says she would be afraid to go back without some proof that you were disposed to treat us justly and kindly; and we have concluded to test your sincerity by asking you to send us our wages for the time we served you. This will make us forget and forgive old scores, and rely on your justice and friendship in the future. I served you faithfully for thirty-two years, and Mandy twenty years. At twenty-five dollars a month for me, and two dollars a week for Mandy, our earnings would amount to eleven thousand six hundred and eighty dollars. Add to this the interest for the time our wages have been kept back, and deduct what you paid for our clothing, and three doctor's visits to me, and pulling a tooth for Mandy, and the balance will show what we are in justice entitled to. Please send the money by Adams's Express, in care of V. Winters, Esq., Dayton, Ohio. If you fail to pay us for faithful labors in the past, we can have little faith in your promises in the future. We trust the good Maker has opened your eyes to the wrongs which you and your fathers have done to me and my fathers, in making us toil for you for generations without recompense. Here I draw my wages every Saturday night; but in Tennessee there was never any pay-day for the negroes any more than for the horses and cows. Surely there will be a day of reckoning for those who defraud the laborer of his hire…

Say howdy to George Carter, and thank him for taking the pistol from you when you were shooting at me.

Jourdon Anderson.