Exposure

Exposing the children to both good and bad of the world, allow them to decide their own future. You don't lay down answers, but make various paths for them to walk on. If we keep hiding what's bad, they will be more intrigued by the bad, and begin taking good for granted. A rational argument …

Feelings

Special moments are special because they are rare. Whether it is good or bad doesn't matter. Once it becomes a routine it loses its value. Don't get used to being happy, find moments of happiness. Don't avoid sadness, deal with it.