The New Hacker's Dictionary served as my whirlwind tour of programming culture, and was one of the first computer-related books I read. Either directly or indirectly due to this book, I ended up: using Emacs, learning Lisp, learning LaTeX, reading (portions of) Knuth's Art of Computer Programming, contributing work to the GNU Project, and generally went on to enjoy programming more than I think I would have otherwise. I didn't learn how to program from this book by any means, but I think it played a notable role in how I developed as a programmer.

That said, the book is woefully outdated, with the last printed edition being published in 1996, and a lot of the topics it covers were kind of old in technology timelines even then.