> The fact that Harari seems to think that everything is just a 'story' that we tell ourselves, is way too nihilistic.
I find that the great challenge that confronts our species is precisely the search for meaning.
There are myriad options for sale in the marketplace of ideas, many coming with pre-packaged meaning. This is the typical case with Judeo-Christian religions, where some external authority dictates meaning to us. But let's suppose that there really is an Anthropomorphic God in the Sky that created everything and has rules for us. Ok, good for him I guess, but you have to lack a bit of imagination to not see the absurdity of that situation. It's just a parent-child relationship, with an imaginary parent, that spares the followers the pain of confronting existential questions, provided that development remains arrested.
The same is true of Atheists and Materialists. Ok, there's only atoms. Everything can be explained as a cold mechanism that progresses from the Big Bang, through evolution, to us and all of our preferences and inclinations. Of course, given that the scientific model of reality is so useful, it is easy to forget that it is just another story when it comes to meaning.
To actually reach adulthood, I believe that one has to confront the scary reality that one is one's own source of meaning. In one sense the universe is made of atoms, in another it is made of stories. Both of these models are useful, but no model can ever spare you from the task of becoming your own source of meaning.