What's a non-fiction book that actually changed your behavior – not just your perspective?

I'm not asking about books that inspired you or made you nod along while reading. I mean books that genuinely altered how you operate day-to-day, made you implement specific changes, or fundamentally shifted how you approach something important.

For me, it was Deep Work by Cal Newport – it completely restructured how I think about focus and productivity. I stopped treating distraction as a personal failing and started treating it as an environmental design problem. I now block out 90-minute focus sessions, keep my phone in another room during work, and batch all my shallow tasks into specific time windows. Sounds simple, but it literally doubled my output and cut my work hours.

I'm curious what books have crossed that line from "interesting read" to "I actually do things differently now" – whether it's about psychology, money, relationships, communication, learning, or anything else that translates to real behavioral change.

I'm always looking for new things to read