Same boat as both of you guys I find myself in this weird world of loving Go's simplicity, loving Rails get shit done mentality + community and Java reliability (but SpringBoot makes me sad).
I'm glad I ventured out of my Java only mindset however. Lots of interesting things going on but decision paralysis sucks.
Same same but different; I've worked in many, many different languages, but in my heart I'm a Rubyist. Definitely second the "things I've learned from other languages", so much so that I gave a talk about it: https://rubyconf.org/program/sessions#session-1198 (I don't know when the recording goes up :P )
I'm glad I ventured out of my Java only mindset however. Lots of interesting things going on but decision paralysis sucks.