He crashes into people with a smile on his face and, when we're outdoors, rides his tricycle around children playing, threatening to bump into them. Excited shouting and vigorous, active play are normal behavior. As teachers, we can help children channel their energy, but we wouldn't want to stop them from shouting and running in situations where it may be appropriate, such as during outdoor play. If so, he has a problem that needs to be addressed. There are a number of possible reasons for rough behavior, ranging from the physical to the emotional.
Some children are slower to develop impulse control.
Maybe John is still at the stage where wanting turns into grabbing without thinking. John could be using roughness to get attention. Maybe he isn't sure how to start a game with other children, so he runs into the middle of their play without realizing it will disturb them. In addition, John could be anxious or upset due to temporary or permanent stress at home. Of course, no matter what the reason is for John's rough behavior, you can't let him hurt people or destroy their belongings.