Be not angry that you cannot make others as you wish them to be, since you cannot make yourself as you wish to be.
I play to win, whether during practice or a real game. And I will not let anything get in the way of me and my competitive enthusiasm to win.
Some of these kids just don't plain know how good they are: how smart and how much they have to say. You can tell them. You can shine that light on them, one human interaction at a time.