The most powerful programming language is Lisp. If you don't know Lisp (or its variant, Scheme), you don't know what it means for a programming language to be powerful and elegant. Once you learn Lisp, you will see what is lacking in most other languages.

Unlike most languages today, which are focused on defining specialized data types, Lisp provides a few data types which are general. Instead of defining specific types, you build structures from these types. Thus, rather than offering a way to define a list-of-this type and a list-of-that type, Lisp has one type of lists which can hold any sort of data.

Where other languages allow you to define a function to search a list-of-this, and sometimes a way to define a generic list-search function that you can instantiate for list-of-this, Lisp makes it easy to write a function that will search any list — and provides a range of such functions.

In addition, functions and expressions in Lisp are represented as data in a way that makes it easy to operate on them.

When you start a Lisp system, it enters a read-eval-print loop. Most other languages have nothing comparable to `read', nothing comparable to `eval', and nothing comparable to `print'. What gaping deficiencies!