I'm writing to let you know that I've taken a job elsewhere. This letter is really hard for me to write because I'm doing it on my phone after three margaritas at lunch. Working here has been somewhat valuable to me ($42,000/year to be exact) and I've learned so much about how to falsify time sheets. I'd be happy to show my replacement how our department works by not responding to any of their emails and yet ccing them on an dozens of discussions unrelated to their position.
I'm sure you understand, I can't ignore the chance to really get my career moving laterally: it's an exciting offer to do basically the same shit in a different place. Doubtless, you couldn't have gotten to where you are without a similar might-do attitude. I'll never be able to thank you for this opportunity, because I don't think I could get through that sentence without laughing. I'll miss many things about the years I spent working here; primarily my youth and optimism.
You were my boss,