This time my note looked like this:
That night A took me aside and whispered, troubled: "Mum, why did you tell me to smile?"
"No reason," I said. "It was just another way to say I love you."
She was confused. "But I know you love me." (OK, so that's good). "So why did you tell me I have to smile? I wasn't sad or grumpy."
"Oh, it doesn't mean that," I said. "It's a cultural meme, referencing the 'smile, Jesus loves you' signs of the 1970s that I grew up with, with which of course you are utterly unfamiliar."
(I didn't say that).
A little while later M said, "Mum, why did you leave us a note in our lunchboxes?"
"Just to say hi," I said. "I've done it before. Do you remember?"
"No." She frowned. "Why did you say 'your mum loves you' ? Why just Mum? What about Dad?"
Ay, ay, ay, ay...