1. "I need a raise."
Never enter salary negotiations talking about what you need -- because of rising costs or a new expense, for instance. Your employer doesn't care about your financial problems. However, management probably does want to reward success and keep high-performing employees satisfied. A raise request should always be supported by evidence of what you've achieved for the company -- along with information about what people with your responsibilities typically earn.
2. “That just isn’t possible.”
Always speak to your boss in terms of what can be done. For instance, rather than saying “We can’t get this done by Friday,” say “We could definitely get this done by Monday, or if we brought in some freelance help, we could meet the Friday deadline.” When you talk to your boss, think in terms of solving problems for her, not in terms of putting problems on her plate.
3. “I can’t stand working with ____.”
Complaining about a coworker's personality usually reflects more poorly on you than on the coworker. Don’t make these kinds of conflicts your boss’s problem. Of course, management is interested in problems that jeopardize the company's ability to function. If you have to speak to HR about a problem such as a colleague's threatening, illegal or unethical behavior, keep your tone professional and the focus on work -- not personal issues.
4. “I partied too hard last night -- I'm so hung over!”
Buck up and get through the day with some ibuprofen, extra undereye concealer and coffee. But don’t share the sordid details of your night on the town with your boss. Even if you have a friendly relationship, he’s just as likely to react with (unspoken) disdain as sympathy. Maintaining a solid veneer of professionalism will pay off when it's time to discuss promotions.
5. “But I emailed you about that last week.”
Alerting your boss to a problem via email doesn't absolve you of all responsibility for it. Bosses hate the "out of my outbox, out of my mind" attitude. Keep tabs on all critical issues you know about -- and keep checking in until you hear a firm "You don't need to worry about that anymore."
6. “It’s not my fault.”
Are you a whiny 8-year-old or a take-charge professional? Assume responsibility and take steps to fix a problem that you did, in fact, create. And if you are being wrongly blamed for a problem, saying “Let’s get to the bottom of this” or “What can we do to make it right?” is much more effective than saying “It’s not my fault.”
7. "I don't know.”
If your boss asks you a question you can’t answer, the correct response is not "I don't know." It's "I'll find out right away."
8. “But we've always done it this way."
You may find yourself with a new boss who wants to try new things -- and the best way to present yourself as a workplace relic is to meet change with a "we do it this way because this is the way we do it" attitude. When a brainstorming session takes place, be part of it and stay open to new ideas. If you have concerns about a new idea's feasibility, say "I think for this to work, we will have to…" Don't kill new ideas with negativity.
9. “Let me set you up with...”
Avoid the urge to play matchmaker for your single boss. The potential risk far outweighs any potential benefit. In modern workplaces, hierarchical structures are often less rigid, and bosses will often end up in semisocial situations with their direct reports. Smart workers will draw the line at "oversharing" -- definitely something to keep in mind if you're connecting to your company's managers on social networks like Facebook.