I excelled at it back in college, but at the time I have to admit that I thought JavaScript was a dying language. And rightly so, in the early 00's JavaScript on the web was commonly used for little more than basic styling or low risk client-side calculations that were hacked together in nasty spaghetti code.
Flash forward a few years and who knew that it would make such a dramatic comeback with developers, getting a sort of revitalization by the community. Not to mention improved support (on the consistency side of things) among browsers.
I found this little gem in my surfing this week, a very impressive re-production of Super Mario, completely in 14k JavaScript no less! Wow!