I suspect that this is partly to do with the kind of work. When I'm working my current day job (computer programming), or writing, or composing music, then that's pretty enjoyable once I get started. When I was working my old job (as a nursing assistant on a psychiatric ward) or if I have to clean the toilet, or wash the dishes or something, then that's clearly less pleasant than procrastinating. I suspect that in Eliezer's case, given that he's engaged in work that is intellectually stimulating and which he considers the most important thing possible for him to be doing, that most of his work falls into the former category, rather than the latter...