I worked in various restaurants for about 7 years before becoming a Software Engineer.

I knew the floor cleaner of one of the larger chains I worked for. He was making $100k+ cleaning 5 or 6 restaurants and this was during the height of the recession. He put maybe 60k miles or more a year and had to get a new car often. The work required him to work 7 days a week overnight. It was extremely hard for him to hire reliable people. His marriage failed in his late 40s due to the hours and never having a vacation.

He did not like the work and it was very backbreaking. The overnight hours ruined his marriage and friendships. Once he had enough money he was going to retire to Costa Rica. One thing he did like was getting new trucks after about 80-100k mikes.