Not many self-employed folks, whether they run a biz or do trades, got complete control over their work.  Sure they dont have a traditional boss, but they gotta keep their customers happy if they wanna get paid and  so even if they call their own shots day-to-day they are still following what the market and their clients want. 

So whats the "real" definition of working for yourself? Id say it comes down to autonomy.  And we are talking more than just how you work, but also who tells you what work to do and, big one here, how you make your money.

Bottom line I dont think its a yes or no thing.  More like a spectrum.  Lots of self-employed folks might have lots of say in their daily grind, but still rely on other peeps to pay the bills.  Maybe working for yourself isnt about being a total island.  More about who is really calling the shots for your career.