I only started to feel the magic and getting addicted after having worked with Common Lisp for a good while, enjoying it AND THEN switching back to another, more mainstream language. Languages like C, Java, C#, Perl, Python, Ruby. Then you discover all the artificial barriers that have been put up in those languages, all the needless syntax you need to remember and the hoops they have to jump through to provide basic Lisp functionality like lambdas.

I have never "switched back" to the likes of Scala or Haskell so I can't speak for those. ML and its brethren have been long on my list of languages to check out and only recently I started playing with Haskell.