Pain Is Subjective

One person may experience pain and find it excruciating. Another person might experience the same level of pain and consider it tolerable.

This is true of physical pain, but also how they perceive the physiological pain of going through something. To one person it is highly stressful and to another it is an easy day.

Regardless if we are talking about going without food, loosing a loved one, or using lethal force, perspectives differ and make a big difference on survival mentality.

To a degree stress, fear, and frustration are emotions we choose. The mental pain we experience is subjective and minimized greatly.

 

Sometimes responses are learned and some can choose a different response. I have seen people using the same reactions as reactions they had witnessed, and upon being confronted with that information and a need to step up and knock it off, they can change.
The part about physiological pain...PTSD from war, abuse, witnessing abuse, accidents, other violence. ..Or repeated verbal, physical, or sexual abuse...not everyone comes out smiling or feeling they won.
Maybe you were only speaking narrowly, like you mentioned..."going without food, loosing a loved one, using lethal force."