Literally a comment I wrote then decided not to post.

> The best LISP is the one you create yourself. You learn so much about programming by implementing your own language, and LISP is brilliant for this purpose thanks to its simple syntax and homoiconicity (code is data, data is code). It's also a great way to learn a new existing language, like Rust or Go, by writing a LISP interpreter with it.

Lisp interpreters are easy to write; a performant and standard compliant Common Lisp system is considerably harder to write.

this is definitely true for forth (: