Don't know if Joe Armstrong ever said anything like it, but I would propose naming an Erlang/OTP analogue of Greenspun's tenth rule (the one about C projects containing ad-hoc, buggy implementations of Lisp) for him.
Any sufficiently complicated concurrent program in another language contains an ad hoc informally-specified bug-ridden slow implementation of half of Erlang.
Any sufficiently complicated concurrent program in another language contains an ad hoc informally-specified bug-ridden slow implementation of half of Erlang.