Dear Mike, [or Mr. Munchak/Hall of Famer]
Congratulations on your new job as a member of a top flight organization like the [insert College, NFL, or UFL team other than the Titans] staff. I hope you enjoy working for a premier coach like [insert any other coach other than Jeff Fisher]. I hope this in no way reflects on your feelings about the current state of the Titans or your dissatisfaction with any of the [think of adjective that embodies inept, dead man walking, sycophant, and choad all at the same time] co-workers that could not hold your jock, but inexplicably share the same offices as you. I would like you to know how disappointed I am that your boss Jeff Fisher would not go to the mattresses to keep you here and that our owner Bud Adams is such a cheap ass that he would not offer you any assurances like [insert appropriate assurances here] to keep such a talented employee like you on staff. Enjoy your future success and though you might feel a little sentimental about your decision, keep in mind this ship was going down despite your best efforts to keep it afloat.
Thanks for the good times and fuck you for leaving,
[insert your name here]
ps sorry for the FU comment [optional]