REPL-Driven Development (2017)
Programming Clojure applications with CIDER[0] is a really slick experience. By connecting through an nREPL port to a running environment you can capture variable values like function inputs, change and re-evaluate function definitions on the fly, and test hypotheses by calling funcs directly with whatever input you want. Not to mention the speed of prototype iteration. This has been invaluable when trying to quickly track down production bugs.I've lately been working in Python, and even with IPython/Juptyer the workflow isn't quite as magical as  Clojure's.[0]: https://github.com/clojure-emacs/cider