"And before you know it you'll be bad at 25 languages, instead of good in one or two that allow you to do what needs to be done." I'm not sure that follows. Ev

"And before you know it you'll be bad at 25 languages, instead of good in one or two that allow you to do what needs to be done." I'm not sure that follows. Even if you choose to specialise in one stack, it is healthy to see a diversity of solutions and opinions/trade-offs in solving similar problems across different stacks. Even if you don't end up mastering any of those, exposure to those can help inform how you approach problems in other languages. A lot of great ideas in modern ecosystems were stolen/inspired from lateral solutions (e.g. using immutable datastructures with React from the ClojureScript world, Netflix's Falcor influencing om.next in the other direction).