Lisp - A thinking man's language

SQL, Lisp, and Haskell are the only programming languages that I've seen where one spends more time thinking than typing.
— Philip Greenspun, March 2007^[1]

[1] http://en.wikipedia.org/wiki/Lisp_(programming_language)#Quotations

One common property of all these languages is that they are all declarative programming paradigms and not imperative programming paradigms.