So last semester for my English class, I had to learn a "new skill" and write an essay [the final] about it. So naturally instead of taking the time to learn something new, I just slapped together a c# (in which I'd say I'm already fluent) calculator app with winforms.

When it came time to present my "new" skill to the class, everybody was overimpressed. Then at the end of my little presentation, one guy goes "Oh! Is that all done in HTML?".

Without giving it a thought, I instinctively replied "No, it's a programming language". He just looked so confused after that.