Only humans invent moralizing gods who monitor our behavior.

What happened in the milliseconds before a behavior to cause it? That's in the neurobiological realm.

Hormones influencing the sensitivity of the person to environmental stimuli.

Importantly, rather than promoting aggression, testosterone promotes whatever is needed to maintain status when challenged.

Finish this lecture, go outside, and unexpectedly get gored by an elephant, and you are going to secrete glucocorticoids. There's no way out of it. You cannot psychologically reframe your experience and decide you did not like the shirt, here's an excuse to throw it out - that sort of thing.

The frontal cortex is an incredibly interesting part of the brain - ours is proportionately bigger and/or more complex than in any other species.

If I had to define a major depression in a single sentence, I would describe it as a "genetic/neurochemical disorder requiring a strong environmental trigger whose characteristic manifestation is an inability to appreciate sunsets.