One evening, Milton shows his wife their latest telephone bill. "Rose, you just have to cut down on your calls. This bill is for over $300 and that's a very high cost for just 1 month."

"You're right, darling," Rose says, "I promise to do my best to curtail my calls."

"Thanks," says Milton. Milton starts to monitor the calls on a daily basis and is pleased to see that Rose is keeping to her promise. But then gradually, as he thought would happen, he sees the daily elapsed time start to increase again.  Then one evening, as Rose dials a number and makes another call, Milton decides to discuss the situation with her when she puts down the phone, whenever that will be. Fifteen minutes later, Rose puts down the phone.

"What a surprise," says Milton sarcastically, "how come such a short call?"

"Oh, it was a wrong number, darling." she says.