My father works partly 18h a day for several weeks only with breaks for fast eating and 3h sleeping. It's not like that he enjoys it much. But as a self-employed you have to work that much if you want to keep your customers (delivery date is in the quote, so you have to deliver). He has done that for the last 40 years haha since I know him never had been different.

I'm the same, I like to work.