I have never been happier than I was in grad school (the Space Systems Lab at the University of Maryland). Which might sound surprising, given the pay and work hours... but there's a lot to be said for working with a group of people you love with all your heart, who have your back, in a field you are passionate about and have been since you were a kid. Grad school was incredibly hard work, and the pay sucked. But I w…
(I get the impression that the trend has been gradually towards more structure and less autonomy in "doctoral programs" -- from my point of view, that's sad).
PS. did you follow Akin's Laws?