As the boss, you just may be the most competent, hard-working person in your organization. You can do any job in the place better than anyone else. So you end up doing practically everything yourself.
You want everything done perfectly, and you figure that in the time it takes to teach somebody else to do a job, you could simply do it yourself. You may be right, but you’re simply trading long term efficiency for a short term fix. A dumb idea, if you plan for your company to be around for awhile.
If there’s a lower level job to be done, give it to somebody else to do. If you did it yourself, you’d give it a low priority and push it aside to get the big stuff done. Result: the job may be late, or poorly done, just because you ran out of time, and couldn’t give it your best shot.
But when you, as the boss, give it to an employee, it becomes a high priority for him/her to get it done right, and on time. Maybe you may have done the job better yourself, but now it’s done – and your world moves on.
That’s what employees are for.