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.

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

Stress is not a state of mind... it's measurable and dangerous, and humans can't seem to find their off-switch.

...when doing science (or perhaps when doing anything at all in a society as judgmental as our own), be very careful and very certain before pronouncing something to be a norm - because at that instant, you have made it supremely difficult to ever again look objectively at an exception to that supposed norm.

Almost always, genes are about potentials and vulnerabilities rather than about determinism.

Only humans invent moralizing gods who monitor our behavior.

But if you get chronically, psychosocially stressed, you're going to compromise your health. So, essentially, we've evolved to be smart enough to make ourselves sick.