It's said that the most effective person is not necessarily the one who does the most, but the one who gets the most done.
Knowing the difference between the two means the difference between being stressed and busy and never feeling like there are enough hours in the day and a sense of ever increasing accomplishment, as you marvel at just how much you can achieve when you get out of your own way.
It seems to me that most business owners fall into 'Do-It-Yourself-It is' - even when we understand the importance of working ON the business versus IN the business.