Alison Green

Saying the wrong thing to your boss can really damage your career. From refusing to work with a colleague to bragging about your irreplaceability, here are 10 things you never want to say to your manager:

1. "Can you write that down for me?" When you're talking about the details of a project, writing notes to consult later is great. But you need to take them yourself, not ask your boss to do it for you.

2. "I just booked plane tickets for next month." Never book time off without clearing it with your boss. There might be a major project due that week, or she might have approved others to have that time off and therefore need you around. Check with her first before you do anything irreversible.

3. "My bad." There's nothing more frustrating than an employee who has made a mistake and doesn't seem to think it's a big deal. When you make a mistake, take responsibility for it, figure out how you're going to fix it, and make it clear that you understand its seriousness. Responses like "my bad" sound cavalier and signal that you don't take work seriously. Don't use it for anything other than the most minor mistake (like spilling something in the kitchen, which you then promptly clean up).

4. "I can't work with Joe." Refusing to work with a colleague is an unusually extreme statement and may mark you as difficult. Instead, try something like, "I find it hard to work well with Joe because of X and Y. Do you have any advice on how I can make it go more smoothly?"

5. "I don't know what you'd do without me." No one is irreplaceable, even the head of your company. Statements like this mark you as a prima donna who feels entitled to special treatment … and will make a lot of managers want to show you that you're wrong.

6. "Do this, or I quit." Whether you're asking for a raise or requesting a day off, don't threaten to quit if you don't get your way. If you don't get what you want, you can always think it over and decide to quit, but if you use it as a threat in the negotiation itself, you'll lose your manager's respect and poison the relationship.

7. "I have another offer. Can you match it?" Using another job offer as a bargaining chip to get your current employer to pay you more money may be tempting, but it often ends badly. First, you may be told to take the other offer, even if you don't really want it—and then you'll have to follow through. Second, even if your employer does match the offer, they'll now assume you're looking to leave, and you may be on the top of the lay-off list if the company needs to make cutbacks. If you want a raise, negotiate it on your own merits.

8. "What's the big deal?" Statements like this are dismissive and disrespectful. If your manager is concerned about something, you need to be concerned about it too. If you genuinely don't understand what the big deal is, say something like, "I want to understand where you're coming from so we're on the same page. Can you help me understand how you're seeing this?"

9. "I can't do X because I need to do Y." Don't say that you can't do something your manager is asking of you. Instead, if there's a conflict with another project, explain the conflict and ask your manager which is more important.

10."That's not my job." Protesting that something isn't in your job description is a good way to lose the support of your boss. Job descriptions aren't comprehensive, and most people end up doing work that doesn't fall squarely within that job description. (That's what "and other duties as assigned" means.) You want to make yourself more valuable to your employer, not less.