I used to love developing in Actionscript 3 / Flash. I've yet to find a language / environment I like more. There was an interesting point in an interview that

I used to love developing in Actionscript 3 / Flash. I've yet to find a language / environment I like more. There was an interesting point in an interview that Lex Friedman did with Brendan Eich, where Eich mentioned that Actionscript 3 was in fact based on a proposed "Javascript 2" language, which otherwise never saw the light of day, due to whatever corporate manoeuvring was occurring at the time. I wish it had been adopted for the browser!