Most people think that working for self is the next best thing after bread,....not always the case. Unless you own an oil well or have virtually no competition and the world can't get by without your products/services, you need clients.
And clients can be the most demanding people out there. I work in a corporate, I have seen some of our suppliers dragged in at ungodly hours of the night (IT stuff), taken thru their paces by demanding and egotistical bosses ..and I quietly mused whether that's what the guy had in mind when he started the business ....