The twin benefits of truly feeling emotion

During a two-hour drive to Olympia yesterday, I saw evidence of an essential truth: my capacity to be kind and patient when triggered is directly related to my ability to truly own the emotion. Conversely, the less aware I am that there is a strong feeling arising, the more likely I am to be harsh, critical and even mean. Consider two scenarios:

Scenario A

1. I feel afraid, sad or angry
2. The witness capacity evokes an awareness that I'm having an experience of some kind
3. Curiosity leads me to wonder what this experience is
4. I notice my physical sensations and/or emotions
5. I name them to myself
6. Once I name them, an awareness arises in me that this is an Amiel moment, i.e. stay connected to Amiel
7. I may or may not reveal this experience to the other person (using "I" language and naming the emotion). Either way, my response is calm, dignified, and respectful
8. Things turn out well

Scenario B

1. I feel afraid, sad, or angry
2. There is little or no witness capacity
3. I respond quickly and often angrily
4. The breath shortens, the mind narrow, and the vision contracts
5. Things turn out poorly

Question: who or what controls whether or not the witness capacity arises in such moments?