It sounds like some of the jobs the poster had ended due to things outside his control. For the rest: Did he decide that he didn't like the line of work? Was he anxious to rebuild everything with the JS framework he saw last night, but couldn't?
I'm fairly pragmatic when it comes to tech. With my last job it was heavy on HTML and CSS which I was fairly green at (alright -> decent at now), and there you could say I was a little over my head, but I don't think there were any conceptual issues I couldn't grasp. Obviously you can spend a lifetime learning on how to best rendering pages and modern browsers.