I love the books of Svetlana Alexievich (not exactly cheerful though)
- voices from Chernobyl
- the last of the Soviets
- the unwomanly face of war
Also, Stasiland by Anna Funder in a similar vibe
And if you're in a really good mood, Gulag Archipelago by Soljhenitsyn is absolutely fantastic.
Really enjoyed Seven brief lessons on physics by Carlo Rovelli.
The Idiot Brain by Dean Burnett, really interesting and easy read about what we know (and don't know) about the brain.
A Short History of Disease by Sean Martin, an overview of how civilisation dealt with pandemics over the course of history
The American Coddling of the American Mind by Jonathan Haight, about what's happening now in American campuses.
Chavs by Owen Jones (this one was particulary interesting for me as a EU citizen living in the UK, I had an idea of the class system but not much of the scale)
In terms of self growth, I enjoyed Atomic Habits by James Clear, Start with Why by Simon Sinek, and Make Time by Jake Knapp and another guy.
Got the books of Simon Sebag Montefiore about the Romanovs, Jerusalem and Stalin in my reading list this summer.