We've talked about qualities that will impress your boss , but sometimes the ones that don't impress her are just as important. The fate of your career rests in your boss's hands, so tread carefully and read on for six things she doesn't want to hear.
Discussing Your Co-Workers' Salaries
Finding out a co-worker makes more than you never feels good, even if there are valid reasons behind the discrepancy. But no matter how you found out or how it makes you feel, bringing up your co-workers' pay to your boss is definitely off-limits — it's unprofessional and will put your boss in an awkward position. If you want to use that information to negotiate a higher salary, use Salary.com or a similar site  to find out the industry standard and present that to your boss instead.
Claiming a Task Is Impossible
It's important to let your boss know if your workload or a project is seeming unmanageable, but approach it carefully. In one office where I worked, the administrative assistant told our boss that her job was impossible and unreasonable. The problem was, several other people had already held that exact position and had performed it with no problem. So instead of getting support and a lightened workload, the assistant got replaced with someone who could get the job done.
Implying You Have One Foot Out the Door
It's courteous to give your boss plenty of notice  when you’re looking for a new job, but there's a fine line. If you're actively interviewing and your departure is imminent, by all means, fill her in. If you've just decided you want to move on and are starting to check out job listings, stay quiet. Your job search may take longer than you think or you might change your mind, and once you tell your boss you're on your way out, she won’t view you or your commitment to the job the same way.
Listing Things the Company Should Be Doing Differently
If your boss asks for this kind of feedback, by all means give it to her — tactfully and constructively, of course. And scheduling a meeting with your boss to discuss concerns is valid, too. But offhanded criticisms of the company with no real solutions behind them will only serve to make you look unprofessional and uncommitted.
Giving an Ultimatum
Threatening to leave if you don't get that raise or promotion may seem like a great bargaining chip, but this move is more likely to backfire than not. Your boss may tell you that what you're asking for simply isn't possible, in which case you're forced to either follow through with your threat or eat crow.
Oversharing About Your Personal Life
Letting your boss in on some of the details of your personal life is a wise decision — it makes for a more comfortable work environment and may make her more understanding of your personal commitments. But don't overdo it ; your boss doesn't need to know that you’re exhausted because you were up late fighting with your boyfriend, or that your hangover is making you unproductive. Too much information is unprofessional and can start to sound like made-up excuses.