I hear you are frustrated, but please understand that a six-year-old really doesn't need to be good at anything, other than being a six-year-old, even if he is highly or even profoundly gifted. Both of my kids were/are a little like you are describing. My DD is now 11, and I can see how her lack of focus when she was younger really wasn't a problem. She doesn't even have a tremendous focus now, and I really am okay with that. Both myself and my sister found our focus much later in our lives – in our 30s. Children learn best by playing. It sounds like your son loves to do that. How lovely that he has a good time socializing. That is an important part of life. Finally, I would like to chime in for creativity! Creativity often looks absolutely nothing like high achievement. In fact, it may not look like very much at all. i bet when your son is "doing nothing," there is actually a lot going on.
