Do people really want to work???

Work today has me wondering....do people really want to work???
I came into work today to find that a project that began last Friday, had yet to be completed. The person who started it on Friday, did not take the time to finish it, just left it with parts here and there. He did not leave a note for the weekend shift or tell them anything about it. 4 different people worked the weekend, not 1 of those 4 people attempted to complete the project. They just left it sitting around for the other employee to finish when he returned on Monday. The thing was, anyone could have done this project. It was basically just a cleaning project, but the words I heard when I came in were " so and so was suppossed to do it"," I didn't know I was suppossed to do that", and my least favorite phrase as a manager "that's not my job". I could have screamed. Maybe my expectations are too high. How do you tell an employee in a nice way that you expect more than just the bare minimum? Has anyone discovered how to teach common sense??