I love that my experience with software is so rich with documentation: the output of -h/--help, man pages, GNU info pages¹, README files in repo roots, code comments, commit messages (especially those rare but wonderful annotated git tags which explain the why and how of features being merged!), printed books about tools that have been stable and useful long enough to earn that honour, specification docs, mailing list archives... it's so deep and rich, so satisfying to read.
¹: yes, yes, I know