Cats aren't hard to train, you just have to make them think it was their idea to do it
Cats truly are trainable. I had a friend who trained his cat to say his prayers before each meal. The cat would hop up in a chair, put both paws together on the table and put his head to the top of his paws. He'd hold that until my friend said, "Amen!"
I've seen a cat use/flush a toilet, too....but the toilet had a chain flush...with a metal hoop on the end....the cat put his paw into the hoop and, with just a little weight applied, the toilet would flush.