A boy asks his father to explain the differences among irritation, aggravation, and frustration.

His father picks up the phone and dials a number at random. When the phone is answered, he asks, "Can I speak to Alf, please?"

"No! There's no one called Alf here," says the person who answered the phone.

His father hangs up. "That's irritation," he says.

He picks up the phone again, dials the same number, and asks for Alf a second time. "No-there's no one here called Alf. Go away. If you call again I shall telephone the police," the person says.

His father hangs up and says, "That's aggravation."

"Then what's frustration?" asks his son. The father picks up the phone and dials the same number a third time.

"Hello, this is Alf. Have I received any phone calls?" he asks casually.