I registered for a couple of Coursera and Udacity courses, figuring I'd do them on the side while not working, but soon dropped out of them when I noticed that I didn't have the energy for both my job and the courses. (I never even got to the point of figuring out whether they were easy or hard - by the time I was done with my day's work, even looking at the course homepages in order to look at the lectures and read the exercises felt like too much effort.)