Greenspun's tenth rule: Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp.
The good news is that with V8 and ES2015, we now have a formalized, (fairly) fast, and tolerably buggy implementation of Half of Common Lisp. Oh yeah, and it runs natively on devices owned by literally billions of people.
Now let's add Javascript to the list.