I've read "The Gay Science", I like some of his work, there are some really great insights regarding personal relationships and the nature of work, and how it affects people. You can't take it all at 100% face value, but quotes like
“Those who commend work. - In the glorification of 'work', in the unwearied talk of the 'blessing of work', I see the same covert idea as in the praise of useful impersonal actions: that of fear of everything individual. Fundamentally, one now feels at the sight of work - one always means by work that hard industriousness from early till late - that such work is the best policeman, that it keeps everyone in bounds and can mightily hinder the development of reason, covetousness, desire for independence. For it uses up an extraordinary amount of nervous energy, which is thus denied to reflection, brooding, dreaming, worrying, loving, hating; it sets a small goal always in sight and guarantees easy and regular satisfactions. Thus a society in which there is continual hard work will have more security: and security is now worshipped as the supreme divinity. - And now! Horror! Precisely the 'worker' has become dangerous! The place is swarming with 'dangerous individuals'! And behind them the danger of dangers - theindividual!”
are more relevant than ever, and yes, he went deep into the waters of insanity with his later work, and Nazi stylings about perfect genes and race, and all that shyt, or so I am told, as I have never read it.