A slight tangent, but as someone who literally just finished grad school (my dissertation was accepted Wednesday): EVERYONE HATES GRAD SCHOOL. IT IS HELL. It is hell in both the near and far views. If people only stayed in grad school because they enjoyed it, there would be no grad students. Forcing yourself to keep going (through beeminder or lots of therapists or support groups with like-minded friends or alcohol or all of the above) is pretty much how you get a phd, and frankly the faster you can force yourself to work through the hell, the faster you will get out. The example the OP gives, of the grad student who floated through grad school without a plan or purpose (which is unfortunately common), seems more likely to be the result of someone NOT pushing themselves forward; if they had been pushing, they would have realized they didn’t have actual work to do.
One of my beeminder goals was to do 20 hours of actual research work a week; weeks when I found it hard to hit that goal were often weeks where I didn’t know what to do, which was a giant flashing neon sign that I needed to go back to the drawing board and figure out what made the most sense to do next. Filling up your time with teaching or classes or other make-work is a way to feel like you’re moving forward even when you’re not, which I guess is another vote in favor of keeping careful data; I know my neurotic time-tracking habit has helped me identify “false progress” multiple times.