As Derek Thompson says, the word "flow" implies an effortlessness, but really, it's the *effort* - just enough, not too much - that defines flow-states. We aren't happiest in a frictionless world, but rather, in a world of "achievable challenges":
www.derekthompson.org/p/how-zombie...
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derekthompson.org
How ‘Zombie Flow’ Took Over Culture
Or: If you're so smart, why aren't you happier?