I've had the same quandary as you. Mainly work with Java and Javascript at work, so I wanted to add a purely functional language. I flirted with Haskell, Scala,

I've had the same quandary as you. Mainly work with Java and Javascript at work, so I wanted to add a purely functional language. I flirted with Haskell, Scala, Node, Scheme and Clojure and eventually settled on focusing on gaining a better understanding of functional programming with Clojure because it has a familiar platform (JVM), syntax I can understand (sorry Haskell and Scala) and it seems like it's going places. Last year, I maintained a focus on Java and JS because I'm still intermediate level with those and didn't want to distract myself with other languages and paradigms. That was a good choice. For this year, I've made a commitment that any side projects I do, I do in Clojure. I cheated and started in 2014, but I am liking this way of focusing on a language for a year and doing everything in that. Maybe once I have more familiarity with more languages, I will feel more comfortable using the appropriate language to solve a particular problem. However, isn't that part of learning? Using a hammer on nails, screws and bolts and figuring out what the hammer is good at and what it isn't?