A true story from Reader’s Digest:

Recently my girlfriend, Karen, got a job at a local hardware store. "The owners don’t want us hanging out with our friends," she said. "If you stop by, tell them you’re my brother."

On my first visit, I walked to the customer service desk and asked the older woman there, "Is Karen around?" When she looked at me quizzically, I added, "I’m her brother."

She smiled. "What a nice surprise. I’m Karen’s mother."