I'm writing this note to let you know that I'm not going to be around much longer. I'm not going to be a burden, I'm not going to be a bother, and I'm not going to be a disappointment. You're welcome.
I know what you're thinking: "Why are you doing this? What about the bills? The laundry? The Netflix subscription that I still haven't canceled?" And to that I say, "I'm just not doing it."
Don't get too attached. The rent is paid, the utilities are turned off, and the pizza is still on the kitchen counter. You can still eat it.
Thanks for the memories. Or, at the very least, thanks for not calling me for 3 days straight to ask me what's for dinner.
Yours sincerely, [Name]