SCOTTSDALE, AZIn spite of repeated requests from his mother, 12-year-old John Farina refused to brown the ground chuck Monday. "With the things I do around here, I ask you to do one thing to help me get dinner ready, and even that's too much," Farina's mother Karen yelled at the wall of her son's bedroom, where he had been playing a video game since returning from school. "And I don't care if you don't want taco casseroleit's your sister's turn to pick. You chose sloppy joes yesterday, so deal with it." Family sources report that Farina acceded to his mother's hamburger-related demands as soon as she introduced the alternate threat of washing the lettuce.