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.

有时我们会为一些事情感到难过，我们不喜欢告诉别人我们为它们感到难过。我们喜欢保守秘密。或者有时候，我们很难过，但我们真的不知道为什么会难过，所以我们说我们不难过，但我们真的很难过。

——Mark Haddon:The Curious Incident Of The Dog In The Night-Time