This came from Tom Vickery. The author is not known, but the piece seems malleable to your own circumstances.

A teacher starts a new job at a school in San Diego and trying to make a good impression on her first day, explains to her class that she’s a Chargers fan. She asks the class to raise their hands if they too are Charger fans.

Everyone in the class raises their hand except one little girl. The Teacher looks at the girl with surprise and says, “Mary, why didn’t you raise your hand?”

Because I’m not a Chargers fan,” she replied.

The teacher, still shocked, asked: “Well, if you’re not a Chargers fan, then who do you support?”

“I’m a 49ers fan, and proud of it,” Mary replied.

The teacher could not believe her ears. “Mary, why are you a 49ers fan?”

“Because my Mom and Dad are from San Francisco, and my Mom is a 49ers fan and my dad is a 49ers fan, so I’m a 49ers fan, too!”

Well,” said the teacher, in a obviously annoyed tone, “that’s no reason for you to be a 49ers fan. You don’t have to be just like your parents all of the time. What if your Mom was a prostitute and your Dad was a drug addict and a car thief, what would you be then?”

Mary said, “A Raiders fan.”