Never split the difference (Chris Voss): incredible book about dealing with people, after reading you end up seeing most interactions with other humans as negotiations with “black swans” hidden in your conversations.

Thinking Fast and Slow. (Recommended in other responses but I’d have to second this one. Incredible for reasoning about your own reasoning).

What the Buddha Taught: (Walpola Rahula): a short intro to Buddhism. There are some really powerful ideas from this age old religion, that can definitely help you think about your own happiness and what material possessions actually give you.

The Innovators Dilemma: a must read for startup founders, I think it’s the best model for thinking about technology and why startups and adoption often fails.

Atlas shrugged (Ayn Rand): completely transformative book for looking at our world, America particularly. Th perspective it gives you may not be in the best, or most human way, but I’ve found no other book that forces you to empathize with capitalism like this one.