We’ve all come across them: toxic co-workers—people whose infuriating personalities can make your day unbearable. And given the economic climate, it’s not as though we can quit, even if a co-worker makes homelessness look appealing. With that in mind, we asked some experts to identify the seven deadliest pests and tell us how to deal with them. The surprising news? Like everyone else, these insufferable problem children want to be liked and respected, say our experts, and often will change if you point out that their behavior is turning people away. Look at these strategies and give it a try. (Thanks to Lisa Krouse, vice president of human resources at FCCI and the president of the Sarasota-Manatee Human Resources Association; Linda Tiffan of T2 Management Consultants; and Felice Schulaner, the former senior vice president of human resources at Coach Inc.)

The Know-It-All

The Know-It-All always has to be right and must let you know when anyone else has fouled up. He may be smarter than you and exhibits no qualms about letting you know it. This type may be recognized by his constant reminders about what he’s done, who he knows, where he’s been, and how he wears his accomplishments on his sleeve. A particularly foul class of the Know-It-All is The Sniper, who likes to maul his prey in highly populated areas, like meetings.

Effect on the workplace

This person is the antithesis of the team player. No one wants to work with the Know-It-All, so the workplace becomes divisive, and collaboration and the work product suffer.

Solutions:

Linda Tiffan: They’re one of the tougher ones to coach because they’re always right. You can try to extinguish the behavior by ignoring it; but if they’re inflicting real harm or their behavior is chronic, you need to take action. If you have any leverage at all it’s to share with them that they’re losing status with the group rather than gaining it. Point out examples where it’s backfiring, and show them that they’re not accomplishing the intent to impress and win favor.

The Control Freak

This species of co-worker has a deep and maddening need to control his environment. Losing control for this person is downright scary: They envision missed deadlines, misplaced files and chaos. These people, also known as micro-managers, thrive on structure and predictability and feel annoyed and threatened by free-spirited types who need flexibility and creative flow. On the good side, these people—who generally care deeply about their jobs—often ensure the outcome of any work assignment is positive. The more extreme Control Freak, however, is rigid, rule-bound and bureaucratic and constantly peering over co-workers’ shoulders.

Effect on the workplace:

Control Freaks stifle creativity and initiative because other people in the office realize anything they do will never be good enough. You’ll get good soldiers who keep their heads down, and employees who will never take risks or learn new ways of doing things.

Solution:

Linda: Confront the problem, but don’t just throw the complaint in their face. You always want to have ideas about how things could be better. When it’s your boss, confront the Control Freak with a group. The key is to help give him the confidence that doing something in a different way will be OK.

Felice: If it’s accurate, grammatical and legal, the Control Freak needs to ask himself: Could I live with this outcome, this approach? If so, he needs to let this person go with it. Yes, it could be better. But the employee will learn from his mistakes and improve.

Lisa: They need to know that controlling behavior is a hindrance to career development. Explain that they’re never going to grow into that leadership position.

The Backstabber

The Backstabber’s tactics aren’t just annoying; they could actually cost you your job. Particularly noticeable in this breed is the avoidance of responsibility, moving the crosshairs for a failed project or bad idea so they align with someone else’s head. The Backstabber can be deliberate, actively working toward your downfall or, perhaps more dangerously, can be oblivious to his malevolent ways.

Effect on the workplace:

If employees feel they’re going to be stabbed in the back or that someone else is going to take undeserved credit, they will stop sharing. For managers, this is bad news, since they cannot fix what they do not hear about.

Solution:

Linda: Because this behavior is overt and hurtful to another person, it’s one of the easier ones to confront. Let them know we can all be successful here. The Backstabber is more about win-lose, so the more they can see that there’s merit in everybody winning, the greater the chance you can get them to alter their behavior.

Felice: A manager should bring this person in and say, "This is unacceptable. We’re here to work together. You’re alienating everyone. You will not be selected as a leader." As a peer, you need to tell this person, "When you do this it makes me feel horrible. I will avoid projects where I have to work with you."

The Liar

There is more than one kind of liar. The unethical and illegal liar in your midst—someone who cooks the books, for example—is the worst, and there is no strategy for this person but the street or jail. Typically, though, the workplace liar tells white lies or embellishes. The White Liar lies to cover his own tracks—a missed deadline, a forgotten meeting. The Embellisher is the annoying braggart who says he played golf with Troy Aikman and Cameron Diaz last weekend.

Effect on the workplace:

Co-workers see through The Liar immediately. This type is never taken seriously or trusted. They’re considered insufferable bores and marginalized, and management does not view them as good candidates for leadership positions.

Solution:

Felice: If they frequently miss meetings and always have an excuse, leave a voicemail, an e-mail and a note on their desk. If they were supposed to follow up with customers and tell you, "I tried. I left a message," tell them, "Let me call them then." That should stop the behavior because there is no wiggle room. For the person who is not playing by the rules, the person who says their mother is sick for the umpteenth time, it’s a different conversation. It’s about not being there for the team. As a manager, I was never a clock watcher; I don’t care if someone needs time off if they’re getting their work done. This is especially true now when so many employees value flexible hours. Just tell the truth. It’s a positive thing to say, "I’m going to take the day off and I’m going to let everyone know my work is done, and here’s the status of my projects." Then people can deal with it.

The Drama Queen

Your basic attention seeker, The Drama Queen might just be the funniest person in staff meetings. This person could also be the source of the loud sobbing in the next cubicle or the blunt trauma responsible for the broken computer screen. Basically, though, the Drama types are equal parts excitement junkie and crisis hunter. While not a flat-out Liar, the Drama Queen can inaccurately describe the most recent apocalypse, omitting details like (1) they did not die, (2) the break room is not on fire, and (3) Jacob from accounting is not, in fact, Satan.

Effect on the workplace:

This is another person who is generally devalued, even if their work contributions are excellent. People tire of their emotionality and turn on them. If management doesn’t take steps to rein these people in, they will lose credibility as well; and the good people may start to leave to avoid the daily fireworks.

Solution:

Linda: It’s important that [they see] the attention they’re seeking is coming back to them as negative, not positive. For all of these problem characters, ask them the Dr. Phil question: How’s that working for you?

Felice: Sobbing in the next cubicle? They might need therapy. One of the characteristics of leadership is composure. People do not follow people who do a lot of arm waving and say the sky is falling. Tell them, "If you’re feeling like you’re out of control, walk out of the building, take a walk, get your composure. People will be afraid to bring interesting complex projects to you or even to talk to you because they don’t know what will set you off, and that’s career-limiting."

The Whiner

Perhaps you recognize this co-worker by the slang name Danny Downer. Chances are you’ve thought long and hard about slipping powdered Prozac into his morning coffee. Instead you are forced to sit idly by while The Whiner prattles on and on about his unfortunate spot in the office food chain. Yet the only effort The Whiner makes in reforming his unreasonable lot is the initiative it takes to perch like an annoying gargoyle at your cube or tie up your phone line like a 13-year-old. A close relative is The Needer, who demands constant reassurance about her effectiveness and job security.

Effect on the workplace:

The negative person lacks initiative and stifles creativity. They’re discouraging and bring down energy and morale in the entire office.

Solution:

Felice: As a manager, I would tell whiners, "Stop. Your job isn’t to identify the problem; it’s to identify the solution. I don’t want to hear about a problem without a solution unless the building is on fire." As far as The Needer, just tell them it’s a self-fulfilling prophecy. If you tell people you’re less capable, they’ll believe you. If it’s really bad, you need to tell them, "You seem very unhappy here. Every way you think about this company is negative, and those

things are probably not going to change. I would suggest you think about leaving."

Lisa: It’s important to model behavior, and leaders need to make sure the right tone and message are sent to employees. [The Whiner] needs to hear that being positive is critically important to an individual’s success. You spend so many hours at the office, who do you want to be around? People want to be around passionate people.

The Gossip

The Venus flytrap of toxic employees, The Gossip employs wonderfully scandalous innuendo to ensnare curious co-workers in her lethal jaws. It may seem harmless, but The Gossip can kill hours investigating and spreading juicy rumor. The Gossip left unchecked may blossom into The Instigator, who uses gossip to turn co-worker against co-worker.

Effect on the workplace:

Gossiping is addictive and it can be fun—when it’s harmless. But it’s also a major time waster. When it’s cruel, it’s hurtful and can tear the workplace apart.

Solution:

Linda: You’ve got to walk away from the gossip. You have to refuse to participate. When a group of gossips is powerful, a manager can try to seed the organization with new blood, people who don’t share the history. Ultimately, the gossips are isolated. They can choose to get on the new bandwagon or choose to lose their jobs.

Felice: Gossiping is a part of being friendly if it’s innocent. But if people are wasting time it’s bad. Tell The Gossip, "We love to hear your stories, but let’s save them for happy hour." For the negative gossip, you need to say, "We run a professional work environment, and nasty conversations have no place here." Peers need to tell this person, "I don’t want to hear about it."