She tried something really simple.
"I wish Jon would come over and apologize for using the bathroom without asking me if I needed to go first."
Zoe hid the wishing stone and it was perhaps only a few seconds before there was a knock on the door. Jon came in and really apologized.
Zoe was thrilled. A wish had come true and maybe this was the end of the frequent morning arguments.
"Do you need to go to the bathroom?" Jon asked.
"Of course. I'll let you know when I'm done."
She waited for Jon to leave and then took the stone with her, not wanting to risk losing it.