[shadowgovt]

The most impressive thing, to me, about LISP is how the very, very small distance between the abstract syntax tree and the textual representation of the program allows for some very powerful extensions to the language with relatively little change.

Take default values for function arguments. In most languages, that's a careful consideration of the nuances of the parser, how the various symbols nest and prioritize, whether a given symbol might have been co-opted for another purpose... In LISP, it's "You know how you can have a list of symbols that are the arguments for the function? Some of those symbols can be lists now, and if they are, the first element is the symbolic argument name and the second element is a default value."