From  Adhara27, Tales From Retail:

So I work in a big box home improvement store in a military town. We get many international shoppers in the store and I've taken it upon myself to learn a few languages so as to help my customers better.

Today, fifteen minutes before closing, a group of men came up to the counter with some basic construction materials. They were chattering in Russian, which I know to some degree. Their conversation was normal at first, primarily focused on their job.

Then they saw me, and it was like a switch flipped. I know more vulgar Russian than anything else because my friends, being gamers, used it most often. I'm also a short, dorky looking Latina. Very few people believe I speak Russian until I do. The men were saying some pretty filthy things but instead of calling them out, I decided to truly mess with them.

I acted oblivious to their conversation and rang them up, processed their payment and finished bagging their goods. As I gave them their last bag, I spoke up.

Me: Spasibo! Dobroy nochi! (Thank you! Good night!)

The immediate double take they did almost broke my composure. The boss particularly went red as a tomato and babbled out a quick apology. The rest of the men looked like they wanted to leave as soon as possible.

I love being multi-lingual.

-- Adhara27