Clearly Communicate Your Expectations

The children have been called to come eat.

Parent: “Billy and Mary, it’s time to eat. You have 30 seconds.” 
Note : When the children are called, the parents should use a pleasant voice, even a lilting voice, during which time the expectations of the parent are restated in brief detail. As the children come to the table on time, be sure to acknowledge that.
Parent: “Thanks, for coming to the table when you were called. I really appreciate that.”
Billy: (Muttering under his breath) “That’s the dumbest thing I ever heard of.”
Parent: (Changing the subject) “Mary, what exciting thing happened to you at school today?” 
Note : At this point, any number of responses might be forthcoming from either of the children. In any event, it is important that the parent be certain to not attend to any of the mouthy, sullen, disgusting, age-typical, inconsequential behaviors. Rather, the parent should move the discussion along in a positive way, picking up on cues that are provided by the children as to which responses to attend to and reinforce and which responses to simply ignore and allow to die on their own. When handled correctly, with lots of reinforcement being given to appropriate behavior, even the most sullen, disgusted, out-of-sorts child will enter a discussion in an attempt to get a few of the goodies the parents are so lavishly handing out.