You're confronted by a colleague you've been gossiping about.

How's this for uncomfortable: A coworker sits down in front of your desk and says, "Is it true you called me incompetent?" You could deny, backtrack, fudge. But you did say it — and you meant it. The best course is to own it, advises Randy Cohen, the original "Ethicist" for The New York TimesMagazine and author of the recently published Be Good: How to Navigate the Ethics of Everything. Tell her why you said it, as constructively as possible. "You say, 'There are all kinds of ways in which you're not doing your job well. You might have done this and this,'" Cohen advises. It may be the most awkward five minutes of your career — and don't expect any happy-hour invitations from your aggrieved officemate — but Cohen says it's OK to express an honest opinion behind your coworker's back, as long as you didn't spread lies or betray a confidence. So what of the snitch? "The colleague who gave you up," says Cohen, "is just a weasel."

A coworker expresses a romantic interest.

You may have harbored Pam-and-Jim fantasies, but before "Sushi? Sure!" tumbles out of your mouth, consider what happens when you find out he's Dwight. "Workplace relationships can go wrong in a hundred ways," says Wash-ington, D.C., attorney Lynne Bernabei, who specializes in sexual harassment claims. "And they usually do." If he's your boss, he could fire you. If he reports to you, good luck getting him to take orders. Bottom line: Don't fish in the company koi pond. "Say, 'Thanks, but I don't go out with people from work,'" says Bernabei. Then buy a fake engagement ring.

You want a raise.

First, find out when the boss is in the most receptive mood — straightaway in the morning? After a lunchtime workout? "You have to get the timing right," advises Selena Rezvani, author of the recently published Pushback: How Smart Women Ask — and Stand Up — for What They Want. A friendly assistant can provide good intel on this. Never ask during an annual review, when budgets are usually tight. Instead, time it to when you look most like a superstar in your manager's eyes. "You have the most leverage after you've completed a mission-critical project," says Rezvani, who suggests teeing off with, "I'd like to talk about my future here. I've learned so much over the past three years and am really proud of the work I've done. I'd like to discuss taking a more senior role — and my pay, which I don't feel reflects my contributions here." Do your homework: Ask around to see what the industry standard is for your job, even whether any colleagues recently received raises — that's useful ammo in a negotiation. If you're getting shut down, table the conversation, but don't walk away empty-handed. Get a commitment to meet again in three months, then book the date.

You're going to miss a crucial deadline.

It's 2 a.m. — again — three days before deadline and you are coming to terms with the fact that you're not going to make it. One thing you never want to do: wait until the morning of, then offer lengthy explanations of what went wrong. Instead, at least a day prior, request a new deadline and specify what steps you'll take to hit it. "Be honest and up front, and communicate to your manager that you have a very clear plan as to how you'll execute," says Shirley Au, president of Huge Inc., a digital branding agency based in Brooklyn, New York. Try: "I need another day on the Penske file. It will be ready by 9 a.m. on Wednesday. I truly apologize for the delay, but it is necessary to ensure it's in tip-top shape and something we can all be proud of. I will, of course, be here until it's done." Then, shut up and get to work.

A colleague hits you up for a donation to a charity you don't want to give to.

If it's a cause you patently disagree with, be candid but tactful, advises Karen Sugar, founder of the Women's Global Empowerment Fund. "Say, 'I'm really glad you're so committed to this, but I have a different position on the issue and just don't feel right giving to that organization.'"If it's a situation where you simply question the particular group's overhead costs, for instance, consider who's asking and why. If it's a close colleague or someone influential in the office, "giving a small gift to support her may outweigh your concerns, say, about how much of the group's money actually goes to research," says Sugar. And if you're just tapped out? Say so. Just don't expect your officemate to dig into her purse down the road for your next walkathon.

You want to quit your job without burning bridges.

Leaving a position without pissing off your manager requires finesse, even if you're leaving for better pay and perks. Because today's boss may become tomorrow's key client or business contact, make sure she doesn't feel blindsided by your departure. If you're leaving because you hate your job, be careful about how you give notice. Your feelings about work should never come as a total shock to your boss. Before you peace out, drop various hints that you're not inclined to stick around — just like you would in a relationship. "You could say, 'I was thinking of going back to school' or 'I'm really interested in getting into marketing,'" says Lauren Zander, cofounder and chairwoman of the Handel Group, an executive education and life-coaching firm. Once your resignation is confirmed, use your remaining two weeks (standard exit protocol, though you may be asked to stay longer) to leave your successor in the best possible shape. Tie up loose ends, leave thorough handoff memos, and be sure to thank your boss on the way out. You never know when your paths will cross again.

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You're an emotional wreck at work.

Your fiancé broke it off, a pet died, your rent check bounced. Whatever the crisis, you simply can't keep it together. What do you tell your boss when you're just plain losing it at your desk? If you can't work at home or take a few days off, level with your supervisor, says Joy Chen, CEO of Yes to Carrots cosmetics. But be a grown-up about it. "Come right out and tell your boss, 'I am going through something personal right now that's difficult for me to talk about. I will do my best at work, but if I am not performing, please call me out on it. I really appreciate your understanding and flexibility.'" If she presses, you may have to fess up the details — but be sure to save the weeping for the ladies' room and not her office.

You need to tell an employee she's dressed inappropriately.

Image is everything, and in these pinched economic times, companies are mindful of every situation that could compromise business, says Tara Lowenberg, founder of TLCommunications, a New York — based PR agency that reps Sonia Kashuk for Target, Oribe Hair Care, and other wellness and lifestyle brands. If an employee is dressed inappropriately, Lowenberg will pull her aside and say, "What you wear is a direct reflection of how you're perceived by coworkers and clients. So what do you want your clothes to say about you?" Be explicit about what's not working — cleavage, skirt length, a sheer top — and advise her on how you'd like the situation remedied. (Should she go home and change?) If the problem persists, send out an office-wide memo. "This way it's in writing and not directed toward one person, although they will most likely — or hopefully — know it pertains to them."

You're at a business lunch, desperately trying to stick to your diet.

You don't want to be that person — the one who asks the waiter 23 questions about the Greek salad, then orders steamed tilapia with lemon on the side. Diets happen. And you're entitled to eat what you want. But there's no need to harass the poor waiter or annoy your companions with your diva demands. Krista Vernoff, a Hollywood television writer (Private Practice, Grey's Anatomy) and coauthor of The Game On! Diet, suggests this approach: Study the menu beforehand (chances are it's online) and decide what you're going to order. When the time comes, do so quickly and confidently. If colleagues ask questions, avoid the word diet, as "it triggers weirdness in everyone," Vernoff says. Instead, say,"I'm on a new health kick. I'm sure it'll be over next week."If you keep it light, you'll impress your business associates without guilting them for diving into the bread basket.

You spammed the office with an e-mail not intended for general consumption.

Whether it was your new favorite meme blog or a photo of your Blake Shelton tramp stamp, that e-mail wasn't something the SVP or mail room supervisor really needed to see. Resist the urge to spam everyone with an apology. "That will only keep the embarrassment top of mind," says Jodi Glickman, author of Great on the Job: What to Say, How to Say It: The Secrets of Getting Ahead. Instead, apologize via e-mail and in person to your supervisor or management team. Glickman suggests the note goes something like this:I am terribly sorry about that e-mail that just went out. That was clearly inappropriate and not meant for the office. This will never happen again. "Make it clear you're both remorseful and aware of the repercussions, that you take the issue seriously, and you've learned a lesson the hard way."

Someone interrupts you in the middle of an important point during a meeting.

You're in a groove, building up to your big finish, when a colleague jumps in and hijacks the floor. You can't let it go or "you'll just be steamrolled," says Jen Bekman, a tech exec turned gallery owner and founder of 20x200. On the other hand, trying to wrench the conversation back may come off as aggressive. The trick here is polite assertion. If there's no obvious opening, wait until he's stopped talking, then say, "Can you give me a moment to finish my thought? I wasn't quite done yet."To avoid these awkward moments in the first place, practice defensive speaking. "If you formulate your thought and have a confident cadence, you reduce the chances that someone else might interrupt you," Bekman says.

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