Sometimes we get sad about things and we don't like to tell other people that we are sad about them. We like to keep it a secret. Or sometimes, we are sad but we really don't know why we are sad, so we say we aren't sad but we really are.
The Curious Incident of the Dog in the Night-time: Vintage Children's Classics (ed. Random House, 2012) - ISBN: 9781448139859