I work 7 days most of the weeks but its physical labor. (the mind is reserved for personal use) I've convinced myself that the joy of relaxing depends on how hard you've worked and that the longer you relax the less enjoyable it gets. You pretty much have to get back to work asap.

I stay productive by eliminating idle time between tasks. Switching should be seamless. If at any time you don't know what you are going to do after you've done the thing you are doing you are doing it wrong.

My coworkers all work harder than I do. End of the shift I've done just as much but they are totally worn out (when I go to my next job)

I do procrastinate for a total of 20 min or so by spending excessive attention on details. This amuses me greatly specially when it infuriates coworkers.

It is like a sport, the work it self is not important it is all about the experience. If I ever get bored with this routine I take 3 or 12 months off right at that very moment. The thought is very comforting. No way I'm going to push it into burnout.