"It amazes me how some programming language authors seem to be clueless about really major areas of our field."

I saw Larry Wall speak within the last year or so about Perl 6. His presentation on the stuff inherited from Perl 5 was solid, but when he started talking about the other things that were more functional and/or "like Haskell", there was a marked change in his confidence and depth of description. I saw him go to dinner with some people organizing the talk and when asked about what other languages he had studied besides Perl, I recall his answer was something along the lines of "well, lots of Perl is written in C." I came away with the impression that he didn't study other languages in order to improve Perl, and the more functional stuff in Perl 6 was coming from somewhere else.