Having an opinion about something is a good thing or a bad thing is a matter of perspective. However, forming opinion helps in certain ways:
1. You develop clarity in your thought
2. It gives a sense of self-concept and self-esteem
3. It enriches and oils your mind
4. It helps you in broadening your wisdom and stretches your horizon
On the downside, you may be termed as judgemental or may develop a flawed or ill-informed opinion but it is perfectly ok. Its the process which is important.
The key question is can you form an opinion about your employer? The answer is off course yes.
Can you form a negative opinion against your employer? The answer is again a simple yes. When you are employed by someone, you are not selling your soul or your wisdom. You only sell your skills. Can you express your opinion publicly? Now this one is tricky because many employers simply fire their employees if they say anything negative about him. But this isn't as simple as it seems. What if you are a government employee or what if your employer is asking you to do things that are against your wisdom? Are you supposed to simply sit silent?
Well even in such scenarios, one is well within his right to express his opinion in private. You can raise the issues directly with the employer through internal channels. You can also raise the points through symbolic protest. It makes you more loyal and responsible if you take the charge and have courage to call a spade a spade.
Enough for the day.