“Look Mommy, there’s a button on the table!” said the kid. “Yes, I think it came off Daddy’s pants.” Silence... a bit too much silence. “What are you doing!?!?” Tableau of horrified little boy crouched over the hot-air vent, looking up with crumbling face as he realizes he’s Done Something Wrong. There is, after all, no argument from first principles (those available to a four-year-old, anyhow) that you shouldn’t drop a nice shiny button down the heating vent. Subsequently, parents observe that uncontrollable giggles seriously impair both the solemn lesson about Not Dropping Things Down the Vent and the effort to soothe the child’s bruised feelings.