I was working at a videogame store in the South. A tall, tanned, and extremely fit man walked in with his young daughter and asked for the latest hockey game. Now, I'm not usually much of a sports guy, but the Stanley Cup the previous year had been so incredible I wound up following the season and learning a lot about how the game is played. Eager to show off my newly acquired knowledge, as I walked with the customer to get the game, I started explaining all the new features this year.
Here's where I messed up. "Now, I don't know how much you know about hockey, but they really upped the board play mechanics this year..." I said, launching into the most technical description I could muster. The man returned a blank stare and a few of the most awkward seconds of silence I can remember. I realized that patronizing opening was a mistake. Just as I began to open my mouth to apologize, the man responded: "I play for [professional hockey team in the Northeast]." I was dumbfounded. I didn't believe him at first; this team was nearly 1,000 miles away! What would he be doing in this suburban southern town? The nearest pro team was ~150 miles away and even our local team was on the other side of the city.
Neither of us spoke another word as I checked him out. He wound up paying with a credit card, so a quick Google search after he left confirmed what I had feared. I had, in fact, just made a fool of myself in front of a professional NHL player and his daughter.