Owned a vending machine route in my 20s. Would get calls at all hours to come fix a broken machine.
Never told them I had a sick day that day :)
When I was in Abu Dhabi this summer for work, I spoke with a taxi driver from Bangladesh. They come over there on a work contract for various lengths of time. As they only get a portion of the fare, working long hours is required to make their stay worthwhile. This particular guy had not taken one day off for months and planned on working EVERYDAY for a year to make the money he needed to go back to Bangladesh and start a chicken farm (all the while sending money back to support his family). He said coming to the US would be his dream but it was impossible for him to get a visa. Obviously not the type of guy our State Department is looking to allow in the US.