A few days ago the guys pouring concrete at the project made a mistake and I had them take up a couple of meters of concrete (a very popular decision as you might guess).
Yesterday, they were still stressed, so in my infinite wisdom, I decided to play a little joke. I got back from lunch and they had poured a few meters of concrete and I yelled, "stop! no good!" The foreman's shoulders went down in disgust and he looked at me in anger. Then, I laughed and said "good, good! Joke!". The workers got it immediatly and started laughing. The foreman understood a minute later and had a good laugh also. The rest of the day the workers kept smiling at me and saying, "joke! joke!"