Emacs

"I use Emacs, which might be thought of as a thermonuclear word processor."

"If you are a professional writer – i.e., if someone else is getting paid to worry about how your words are formatted and printed – Emacs outshines all other editing software in approximately the same way that the noonday sun does the stars. It is not just bigger and brighter; it simply makes everything else vanish."

"I'm writing this article with software called XEmacs. The program is unlike any other word processor I've ever encountered. In addition to cutting and pasting text, XEmacs can run other programs; send electronic mail; browse the World Wide Web; retrieve, edit, and send files across the Internet; and keep track of appointments. It's like a digital Swiss army knife."

"Emacs is undoubtedly the most powerful programmer's editor in existence. It's a big, feature-laden program with a great deal of flexibility and customizability. … Emacs has an entire programming language inside it that can be used to write arbitrarily powerful editor functions."

"C++ is a badly designed and ugly language. It would be a shame to use it in Emacs."

"Emacs is the ground. We run around and act silly on top of it, and when we die, may our remnants grace its ongoing incrementation."

"An infinite number of monkeys typing into GNU Emacs would never make a good program."

"Personally, I feel inspired whenever I open Emacs. Like a craftsman entering his workshop, I feel a realm of possibility open before me. I feel the comfort of an environment that has evolved over time to fit me perfectly – an assortment of packages and keybindings which help me bring ideas to life day after day."

"Richard Stallman, poem posted in emacs-devel on October 12, 2015"