My eldest has just come downstairs. It's one of his Not Going To Sleep nights 
me "I love you"
him "ok"
me "the correct response is 'I love you too Mum'"
him "WHAAAAAT? That's a stupid response"
Now, happy as I am that it was a well formed sentence, and he clearly knew what 'response' meant
I would have preferred "I love you too, Mum" 