When I was a graduate student I worked hard, but not quite as hard as I felt like I should work.
I often brought home manuscripts I thought I might read before bed, only to take them back to work to read over lunch, and then back home again. I would schedule myself time to do things on the weekend, only to find that I struggled to follow through with my plans unless I had been very explicit: experiment and controls already designed, protocol selected, and sometimes even tubes labeled already.