We live well enough to have the luxury to get ourselves sick with purely social, psychological stress.

But often, it's easier to resist temptation with distraction, or to be so inculcated in doing the right thing that it's automatic, outside the frontal cortex's portfolio - Then it isn't the harder thing, it's the only thing you can do.

As long as experiencing your optimal level of good stress doesn't damage others, it's hard to objectively define where normal enjoyment of stimulation becomes adrenaline junkiehood.

Pulling a gun's trigger can be an appalling act. But if it is suicidal drawing fire to save someone, it has an utterly different meaning. Placing your hand on someone's arm can be an act of deep compassion or the first step of betrayal. The punch line? It's all about context, and the biology of context is vastly more complicated than the biology of the behavior itself.

We live well enough to have the luxury to get ourselves sick with purely social, psychological stress.

What does the frontal cortex do? Gratification postponement, executive function, long-term planning, and impulse control. Basically, it makes you do the harder thing.

On an incredibly simplistic level, you can think of depression as occurring when your cortex thinks an abstract thought and manages to convince the rest of the brain that this is as real as a physical stressor.