The toughest boss I ever had was when I owned my own restaurant.
It seems like a lot of people want to own a restaurant - or some kind of Hallmark-type gift store.
I was a District Manager for Hallmark's largest franchisor. Getting "shrinkage" (theft) below 3% was enough stress to make most of my managers (all ladies) cry when it was review time. Turnover was about 90% a year.
When I owned my own restaurant, my boss had me working seven (and sometimes eight) days a week. I was finally able to convince him that six days a week were enough. The first time I convinced him I needed a vacation, he made me call the restaurant three days during the week I was gone.
Drove me crazy.
After two years, I sold the restaurant to another fool and went back to an easier job - taking baby pictures.