After almost a decade, I still find lots of interesting ways to write plain vanilla JS code that makes developer's jobs easier in lots of interesting ways. Before that, I spent a full decade writing C++ using nothing but a restricted set of in-house libraries. I don't recall ever being bored because I always felt like a carpenter: have a problem? You have the tools to build more tools to make your life easier. I experimented with event driven models vs. streams vs. queues, doing complex calculations by spreading them across the nodes of a tree, developing unit and API test tools (C++ had none, many years ago).
Today, architecture feels more like technology shopping than tinkering.