Burn out is real. It is dangerous, and even an overwhelming, driving passion for your work, your creation, can lead to disaster.
Ed Catmull recounted this story about the production of Toy Story 2 [1]:
"So we came back, John [Lasseter] told the story crew to take a good rest over the holidays, and come back on January 2nd... we were re-boarding the movie.
We had 8 months left.
We then started this incredibly intense effort to get this movie out. It was boarded quickly, it was pitched to the company, it was an electrifying pitch.
We had a lot of over-achieving people working for over-achieving managers to get the movie out.
We worked brutal hours with this. When I say "brutal", we had a number of people that were injured with RSI [2], one of them permanently left the field.
We had, actually, a married couple that worked there. This was in June, so it's summer, and the father was supposed to drop the baby off at daycare, but forgot; don't know why... but came and left the baby in the car, and came into work. Again, as the heat was rising, the mother asked... they realized and they rushed out: the baby was unconscious. The right thing was done, they put ice-water on the baby. The baby ended up being fine in the end, but it was one of those traumatic things, like, 'Why did this happen, are they working too hard?'
So when I say it was intense, it really was intense."