The human body is an amazing thing. If you do something bunches of times in a row it gets fatigued and starts to fail. But if you persist long enough it eventually adusts and can continue for a very long time. Case in point: I did lunges for forty-five minutes straight this morning. (Possibly I misunderstood my trainer.) After 100 lunges my body said "Um, this is rather a lot of lunges!" After 150 it said "Yeah, so, I'm done now." At 200 it said "You know, this is pretty easy!" And then when I stopped at 268 and started home I about fell over. <g/>
Hmmm.... Persist in insanity long enough and it becomes normal, at least until you change something at which point everything collapses. Sure sounds like the software industry to me!