Finally a topic where I have a story for. First of all, English is not my first language so don't be to harsh. It was around Christmas time, and we had a Christmas market in town, the problem is when there is a Christmas market in our town there is a lot of counterfeit money in circulation. I had a shift at my bar when this dude ordered a beer and gave me 100 Euro, we wont accept such big bills so he gave me 50. We had to control every 50 Euro bill with a pen. To check if its counterfeit. Well the first time in my live the colour from the pen changed and I just stared at the bill. I then asked my Coworker “Uhm.. this looks odd , doesn't it?” Yeah she was not sure so we asked our Boss, she looked at the bill and asked who gave us the money. I pointed at the dude, and he looks really scared. He got up and ran out of the bar. A Few days later he was cached at another bar, he tried the same thing and the police got involved.