When and if you would ever need surgery, would you dare to perform it on yourself without assistance? I can't imagine how you could even do it when you put yourself to sleep?
Selling your house alone with out the assistance of a licensed Real estate professional would be considered much the same.
What Realtors do isn't life threatening the same as surgery would be. However in most cases it's dealing with your largest investment so make sure the knife isn't rusty when you decide to pick it up and save a dollar operating on yourself by selling by owner. AKA as unrepresented seller.