CoffeeScript was written by Jeremy Ashkenas, a Ruby developer who was fed up with the quirks of JavaScript. It was an instant success in the Ruby community. Many people were tired of having to type === instead of ==, of JavaScript's crappy lexical scoping, of having to jump through hoops to set up even the most simple inheritance structure, of variables leaking into the global scope or having to worry about silly things like hoisting.
This was a time when web user interfaces were becoming more complex and backend developers had to spend more and more time writing JavaScript code. For a long time, coding in JavaScript meant you spent 100% of your time using jQuery. And what an epic mess that was!
At that time many people did not consider JavaScript to be a real programming language, because of it's oddities. So when CoffeeScript came along developers (especially Ruby developers) embraced it as a way to make coding in JavaScript suck less. I was one of those developers. I liked