Fashion-based-programming leads to endless re-invented wheels and more effort going into running round in circles than looking a bit into history and learning from it. Ruby and Python seem to live in parallel, separate worlds. Oh look, here comes Node.js where everything's written again, this time in JS.

I'm not arguing for monoculture but it's a bit sad to see isolated communities not working together.

Haskell is an example of a language which a good reason to exist: solid unique PL qualities and is also highly applicable to specific problems.