Dear ____________,
Hail to the chief! If there ever was a boss that deserves praise and adulation, that person is you. During all of the years that I’ve worked here, you have never failed to be supportive, kind, and fair to each of your employees. I want you to know how much I enjoy working here at ________________. Thank you for providing such a great work environment for all of us.
Best Regards,
(YOUR NAME HERE)