To me the biggest annoyance about the Ruby community is the belief that they invented everything and know how to do everything right if others would just listen.

And then, through unfamiliarity with what others learned a long time ago, they do it wrong.

As a random example, unit testing has been the standard for perl (note capitalization - I'm referring to the interpreter here) since it was released in the mid-80s, and for the Perl community since CPAN was created in the mid-90s. And when I say standard I don't mean that someone writes tests, runs it, then packages. I mean that - by default - nothing gets installed anywhere until it has passed its full test suite. Furthermore if I release a module to CPAN, I'll get automated emails about every OS and version of Perl that it didn't work on.

Core ruby still does not have good unit tests, and you have to go out of your way to run unit tests for gems. If you do that, you will find that a good portion were only set up for the author to run - they didn't think anyone else would ever do that.

And yet I've had Ruby devs with a straight face trying to tell me that Ruby is awesome for its testing culture, and everyone else has a lot to learn from them.

They are missing a lot, and don't realize it.