define "good".

If it's "knowing one's way around" - then yes, I guess I'm good in the context of some languages. How did I get there?
1. good night sleep (yes, #1; I've learnt from my mistakes during studies)
2. accepting/making up challenging tasks
3. toying around with the tools and abusing them heavily (like creating video games in bash or doing some metaprogramming)
4. when you find it hard to find any material about the tool/language that would be new to you - consider yourself good at it.