Not today, but this week, I started learning JSP. Didn't realize that was something different than Javascript (which run on the browser), but rather, Java Server Pages (which run on the server). Somehow, I've managed to spend most of my career avoiding all but the most trivial GUI work. (I usually do backend work. [cue Steve])
And I already was told I could call myself an expert once I learned how to do Decorators. I think she was being sarcastic, but who cares, the guys who usually do the GUI work are too busy trying to upgrade all the code from Java7 to Java8, and I'm pretty sure I can get it all done in a couple days.
So...pride.