Moishe is getting more and more worried about his wife Sharon's aggressive behavior towards him. So today he decides to see Doctor Levy.
"How can I help you, Moishe?" asks Doctor Levy.
"It’s not about me, doctor," replies Moishe. "It's Sharon. I just don't know how to handle her anymore. Every time I'm with her, Sharon seems to lose her temper for no reason at all - and it's beginning to scare me."
"Don't worry Moishe," says Doctor Levy. "You'll be pleased to hear that curing such behavior is now no longer difficult."
"So what medicine are you going to prescribe for her?" asks Moishe.
"I don't need to prescribe medicine for her," replies Doctor Levy. "Whenever you think Sharon is beginning to lose her temper, just drink some water. But don't swallow it - just swish it around in your mouth. And keep swishing it around until Sharon calms down or leaves the room."
"Thank you doctor," says Moishe. "I will try it as soon as I get back home."
Ten days later, Moishe books another appointment to see Doctor Levy.
"So how is Sharon's temper problem?" asks Doctor Levy.
"Your cure really works, doctor," replies Moishe. "I've been swishing water every time Sharon starts to get aggressive, and she's now almost normal. I can't thank you enough, doctor. But do tell me, how can a plain glass of water work so well?"
"I must be honest with you Moishe," replies Doctor Levy, "the water itself does absolutely nothing. It's you keeping your mouth shut that is the solution."