Your attitude is the way you feel about something.
If someone says you have a “good attitude,” what they mean is that you pay more attention to the good things that are happening than the bad things, or that even when only bad things are happening, you don’t complain.
A “bad attitude” is different. People with bad attitudes complain. They crack mean jokes and sneer at anyone who looks too happy.
Without passing judgment on either of these dispositions, you can see the problem with labelling one “good” and the other “bad” — every situation is different. Sometimes the bad thing to do is keep your head down, follow the rules, and pretend nothing is wrong, and the good thing to do is break a few rules as loudly as you can.
You can also see why someone who was responsible for a bad situation would divide attitudes into “good” and “bad” like this. People who do what she says without complaint are good, and people who undermine her authority are bad.