Personally I started using it I think as everyone else... a lot of years ago in a messy and uncontrolled way.
I'm not proud of it at all but I had no clue of what was going on. I knew I had this language that let me interact with the DOM so I just had to throw some script blocks into my webpage and it was it.
Right now I just love it. It's still a pretty messed up language, with a log of not so logic (at first or even second glance) but once you master it, it becomes a very pleasant environment to work with.
What do you love about it? What do you absolutely hate about it?