Thinking, Fast and Slow took me four months and I don't regret it
On Thinking, Fast and Slow by Daniel Kahneman
This isn't a beach read. I did a chapter or two at a time, usually with coffee. Some of the priming research in the early chapters hasn't held up well, and Kahneman himself later admitted he leaned on it too hard. That's worth knowing going in.
The parts on how we judge risk are what I use. I work in finance in Agrabad and I now catch myself anchoring on the first number somebody says in a meeting. I catch it about one time in five, but that's better than never.