Do you find this hard as a supervisor in general?

I worked in an office for 12 years and I never envied anyone who was a supervisor. Do you find as a supervisor that people tend to take advantage in the work place? Do you find that when workers are required to do more that they get all pissy and annoyed? I never did I knew if I was making $25,000 a year I was going to get $25,000 dollars worth of work. I am job seeking and what does a supervisor look for in a worker and how would I be able to make my supervisors job easier? Because I undertstand that is one of the reasons why I would be working. Thanks for your answers.