Your teen does not come with a user's manual. And just for that reason, some parents treat them like damaged household goods that they no longer have any use for, and consequently pay them as much attention as you would to the broken down vaccuum cleaner lying around in the garage.
"Honey, do you remember that first vaccuum cleaner we got 15 years ago?" "Of course, it must be somewhere in the house, the garage, or the basement. I'm not sure exactly where though. Why do you ask?"
