Can I stop being POA to my mean, cranky suspicious Father (90)?

Goodness knows I've thought about this often enough to look into the steps I would need to take to resign. In my case it is a letter of resignation to the attorney who drew the DPOA up, another to my mom and one to the named successor. No delivery method specified so I would do regestered mail with signed confirmation of delivery. Think it through - once you go through with it - it's done. I keep on, figuring I've put this many years into it and everyday I continue is one day closer to it being finished.

Yes; read the document carefully to see what notice you have to give to resign; write the resignation letter and deliver it according to the terms of the POA. If there's no specification on delivery and you hand deliver it, make sure to get a receipt.