Read the following situation and choose the appropriate answer. Situation: An American invited a group of Japanese students over to his house. He and his wife had spent a great deal of time preparing food and getting the house ready. They were looking forward to the party and hoped that the Japanese would enjoy themselves. They came at about 8:00 at night and right away seemed to be enjoying themselves. There was a lot of dancing and singing and good conversation. Then, almost suddenly, one of the students said “Thank you" to the hosts and said that it was time to go. After that, all of the Japanese began to get ready to leave. The American and his wife couldn't understand why this happened. They felt insulted because everyone left so early and at the same time. Can you explain what happened?