It was normal to wake up with eye crusts (or rheum) in the morning. X, being the OCD child of the two or more aptly described as a Mini-me, was pretty studious in washing his face and eyes to remove the dried-up discharge.
One morning, X asked how these eye crusts came about. Mr H explained that the eyes teared in the night and hardened during the night.
When X heard that, he asked in a very curious manner, if it was because he was sad and teared at night.
The way a X had correlated tearing and sadness was very sweet. Despite his tender age, he actually understood the meaning of sadness. It made me wonder if he felt true sadness when he cried during his tantrums.