Here's the story . . .

It was the girl's very first day of her first part-time job ever -- working as a summer waitress in a typical family-style restaurant. More than anything, she just wanted to do her best and get through the day without any trouble. So she hid her nervousness behind a jittery smile and thought: "Do not make a mistake. Do not make a mistake. Do not make a mistake."

First customer, first order: a chocolate shake to beat the heat of the noonday sun. She took the order to the kitchen and soon received the drink, which she placed on a tray. She then returned to the customer, holding one hand on the glass to keep it steady.