Resignation email

I’m trying to put together a brief, 3 sentence resignation email. I don’t want to thank them for anything, it was not a pleasure working with them and I don’t wish them anything. I’m casual so I don’t even need to provide 2 weeks notice, but because I’m a decent person, I’ve decided to anyway, just so they can’t guilt me in to helping out or stay on till they find someone to fill the position.

Any suggestions? All I’ve got at the moment is “I am writing to inform you of my decision to resign from my casual position as practice manager. My last day of employment will be Sunday 14th January” however that seems a little too cold and unfinished.