Well hey there! Welcome to my little corner of the Internet... Try not to get lost :P
My background is in systems programming, so I've used a ton of back-end languages. Currently, I'm excited about the future of functional programming languages, with particular interest on those that use the actor pattern for distributed computation, like Scala and Elixir. In my spare time I also learn how to build web applications using popular frameworks.
In the age of mobile, concern must be directed to the data that is sent over the wire. Performance improvements will rely on reducing data transfer by steering away from bulky frameworks, using minification techniques that eliminate dead code, and develop progressive web applications to drastically reduce user perceived latency.
Good software engineers actually ship their products, so I take time each year to catch up on the best practices to deploy applications that don't hurt extensibility and testability. Continuous Integration is a big thing for me. At this point in time, it appears that the best way is to deliver applications on a giant blue whale with little blue crates on top :-)