[Florin_Andrei]

It seems like the basic blueprint of the human being, at every level, requires a certain amount of constant stress to function properly, an external challenge to the capabilities or even integrity of the system. At every level. Purely physical (motion), immunity, emotional level, intellectual level, etc.

Unless we change the blueprint in a massive way, we won't do well in a life of complete leisure.

[TazeTSchnitzel]

What humans consider leisure is simply enjoyable work. If there is no "work" work and just leisure, we're fine.

But not if there's nothing to do at all.