I work hundred hour weeks.   I work thirty hour weeks.   Should try to make a point of having an occasional zero week, but I'm not very good at that.  I see similar with friends who have small businesses of their own in other lines of work, say tire shop or lawn care or auto repair or construction or earthmoving.   I know a ton of others who are not self-employed, but who have a main job and a part-time gig on the side for extra monies.  I know pipeliners and welders and linemen who get their butts kicked on the road for big monies, but take the winter pretty much completely off.   I know some farmers who did pretty much nothing but work with no other life to keep their wife happy and gave away a ton of it in a divorce.  

There's definitely flexibility to run a kid to the dentist at 2 pm.

There's also definitely not flexibility to schedule getting tickets to a baseball game or a rock concert on June 9, if you do your own spraying and sidedressing and hay mowing etc etc.....