I've experienced this first hand. It's a surreal feeling, because you know that objectively everything is awesome, but emotionally you want to throw it all away.

I have also experienced burn out with a job that I disliked. In both cases there is a feeling of not being able to focus on the work at hand, that more effort will make you physically sick.

The author's example of eating ice cream at every meal resonates with me really well. You do get tired of it, even if it's conceptually amazing.