Once students of the psychological faculty, after studying conditional reflexes, decided to work out the studied material on one of the teachers. Comrade loved walking around the audience and gesturing, which greatly annoyed everyone. And the guys came up with such a thing, when the prede began to walk around the audience, everyone began to get distracted and talk to each other. As soon as he sat at the table, everyone calmed down and listened attentively to him. After a while it worked. The training was successful! :)