I think you are spot on about this. I used to evaluate a day based on my ability to sell my services, but I have come to realize that this can kill good work. I just heard a very interesting quote this morning that is applicable to entrepreneurs "The planting phase lasts a lot longer than the harvesting phase, and if you think you are in the harvesting phase before you really are- you will not see the growth you think you deserve- which will kill your motivation." This is the same thing that your article was saying- find ways to progress.