The basic premise that children must learn about emotions is that all feelings are okay to have; however, only some reactions are okay.
Like secondhand smoke, the leakage of emotions can make a bystander an innocent casualty of someone else's toxic state.
For better or worse, intelligence can come to nothing when emotions hold sway.
Fear, in evolution, has a special prominence: perhaps more than any other emotion it is crucial for survival.
But the rational mind usually doesn't decide what emotions we "should" have !