Same for me. The book and its tools are extremely empowering. In general, anything from Sanjoy Mahajan (the author) is extremely insightful: -Street Fighting Mathematics -The Art of Insight in Science and Engineering -Lecture notes on signals & systems (a bit harder to find) -Lecture notes on thermodynamics (real-world insights rather than endless manipulations of weird partial derivatives)

Afaik he is currently working on a textbook on mechanics.