What distinguishes a good supervisor or manager from a bad one?

1. A good supervisor listens to what their people need to get the job done.

2. A good supervisor gives his people the tools and the direction, and then lets them work.

3. A good supervisor insulates the staff from the vicissitudes of upper management.

A good manager deals with issues as they arise, rather than ignore or hide form them.
A good manager insists that employees suggest solutions rather than just complain.
A good manager learns to listen to both sides and avoid making snap judgments.

A few things that immediately come to mind that would differentiate a good supervisor from a bad one would be treating everyone equally. If it’s good for one, it should be good for all, and across the board should be the rule to applying the rules rather than the exception.
The second most important thing is having an ability to fire people when they are crappy employees and screw off and don’t do the work they were hired to do.
Thirdly, reward people for good performance and while that may include the occasional “atta girl”, it should also come in the form of pay raises for taking on additional responsibility and job duties.

I definitely agree with a good supervisor should treat everyone equally. No special favors for anyone that the whole group is not getting. Good supervisors also will defend their employees. If there is an issue, a good supervisor should not chastise the employee in front of others if it could be avoided. Any kind of discipline should be behind closed doors. A good supervisor realizes that everyone works differently, so if you give two different people the same task, they might do it two different ways. A good supervisor will not micro-manage, but will be satisfied when the job gets done.

I work for the government, so there are some real nut cases there. I have had a supervisor that was so anxious you could see it in her face. I had a supervisor who liked me until I went out sick, hospitalized with an illness. When I returned, he treated me differently and I ended up getting transferred, which made me happy and I’m sure was a relief for him as well.

I have written about my worst boss here .
My favorite boss is the one I just had for 3 years. She was smart, and fun to work for. I have worked harder the last few years just because she made me want to. It’s too bad the rest of my crew didn’t appreciate her.

@filmfann: maybe there were things that she did that you did not mind or that you liked but that others did not like. I have had experiences where I could not tolerate something about a supervisor but others did not mind it, and vice versa.