Ask the Child, "Why?"
As a coach, we can often see what the children need to do to play better soccer. We have several options ranging from talking, demonstrating, or even clever small-sided games. Rather than delivering to them the "right" answer, we might want to try and educate ourselves instead. Ask the child "Why?". Then ask "Why?" again. Ask five times. We call this 5-why analysis. You will be amazed. Behavior that was mystifying suddenly becomes clear.
Rather than addressing the symptom, you'll address the root cause. In many cases, where you may have been frustrated, you will find yourself smiling. Our children are often doing their very best, even when we can't tell they are. They just have different priorities.