Fear is a response of a threat.............
Therefore fear is not an emotion, rather a physiological response in order to protect us as a species.
This is why a sociopath can experience fear and no other emotion.
Anger is a secondary response to an unresolved primary response.
Anger can be a response to an unresolved fear.
Once again a sociopath can experience anger.
This realisation and understanding has led to a settling and peace, whilst trying to cognitively understand the responses of two people close to me.