We allow firefighters to risk their lives to save others, and we honour them for it. We didn't allow people to test vaccines that way.

You are surrounded by an endless series of expanded layers of social networks. Your inner core is 5, which extends to 50-150, 500 and eventually out to around 1500. As you go out through the networks, the number of people included increases, the average quality of these relationships declines.

Once released, former hostages encounter a myriad of practical issues—closed bank accounts, lapsed insurance, and the need for specialised medical and dental care that isn't readily available. They might also require physical therapy among other medical treatments.

Anyone worth following in peak performance will tell you that 90% of human performance is mental. The understanding of that mental aspect of the game is brand-new – perhaps 10-20 years old. The work being done around the neuroscience of performance is creating an unprecedented rate of change; it's honestly off the charts.

We're the mammal that likes Tabasco sauce! We're the only creature (as far as we know) that seeks out suffering and pain willingly. We do so not just through liberal splashes of Tabasco on our food, but also through seeking meaning through activities.