I started as a backend developer and working with JS currently. I like to explore ES6, HTML5 api, new frameworks and technology. This website is done in google polymer because I wanted to see how it works.. (works pretty well :) )
My philosophy is to do something and master it, to be specialized rather than to do many things and to be average. If I have the knowledge I can think more about the problem itself, rather than how to use the tool.
I find that writing quality code is what defines programmer in the first place. To be experienced and to know many programming languages is cool, but understanding what this means and trying to think in that way is what makes me excited about programming.