NEW YORK (MainStreet) — Whether you're desperate for a job or convinced you're the world's greatest hire, you shouldn't convey that in an interview. Experts say coming across as overly needy or boastful are the quickest ways to rejection. Here's why your attitude may rub hiring managers the wrong way.

If you're too confident ...

Employers are looking for candidates who exude confidence but aren't overly boastful, says Robin Ankton, regional vice president of Accountemps, a division of Robert Half.

"They want to know about your accomplishments and how they relate to the job, but they don't want to hear about why you think you could do a better job than they can," Ankton says.

When you boil it down, an interview is a lot like a first date, says Amanda Augustine, job search expert with TheLadders.

"Confidence is attractive, but arrogance is a turn-off. Who wants to work with someone who has a big ego?" she says. "Employers consider how you behave in the interview to be an indication of how you will interact with colleagues, vendors and clients on the job."

Remember that you're interviewing for the job at hand, says Paul Sorbera, president of Alliance Consulting. Too often people talk about what they "really want to do" rather than selling themselves for the job that's available.

"If you oversell yourself and portray that you have a skill set beyond what the job requires, you're going to be perceived as inappropriate for the job," he says. "You're basically saying, 'I could run the world, but I'll take this job,' and no one wants to work with a person like that."

Hiring managers don't want to hire someone who is going to be bored in their job, says Joe Ungemah, vice president of talent solutions at CEB.

"Don't walk in and say, 'I could do this with one hand tied behind my back,'" Ungemah says.

If you have any doubts about the level of confidence you should portray in an interview, Ungemah suggests researching the company culture before your interview. For example, if you find that the CEO doesn't have an office but sits out in cubes with everyone else, that's a cue that the company is more interested in teamwork than hiring a hero.

"Company culture really makes a difference," he says. "There are some companies where you'll be rejected after the first interview just for being too boastful."

Also, keep in mind that the level of confidence you portray may change depending on how far along in the interview process you are, says Dave Sanford, executive vice president of client relations at WinterWyman.

"At the beginning of process, the burden of selling yourself is firmly on your side of table, but by the third or fourth interview, if you're one of the candidates they're pursuing, you don't have to sell as hard," he says.

With that said, don't be afraid to be assertive, Sanford says. Take the opportunity to tell your story and articulate your value proposition. Be confident without bragging.

"Set yourself apart in such a way that makes the other person sit up and listen. There are a lot of ways to do that without saying, 'I'm the greatest thing in the world and let me tell you five reasons why.'"

If you're too desperate ...

Hiring managers are looking for strength, Sanford says. They want someone who can get up to speed quickly, assimilate into the company culture and take charge.

"If you're too humble, they're going to ask, 'How will this person be able to handle the things I am going to throw at them?' he says. "You're going to come across as too soft, too mushy, too wimpy."

Some people who are naturally humble may need to step up their game and be more confident in an interview, he says.

"If your approach is to assume that the other guy will read between the lines and figure you out — they won't. They are not going to spend time digging through all of the 'Aww, shucks' talk to figure out who you are. You've got to be your own advocate," he explains.

Even if you've been out of work for a while, don't go into the interview and talk about how rough things have been. You may feel like your luck has been rotten, it's a terrible job market and you have no prospects, but keep that to yourself, Sorbera says.

"They're going to say, 'There must be something wrong with this person,'" he says. "Avoid casting yourself as damaged goods. Tell them how you've been following the markets and keeping yourself active. Show that you've stayed up on the industry as much as possible."

Although you may be eager for a paycheck, rein in your neediness, Ungemah says.

"Even if you would kill to work there, don't let them see that as desperation," he says. "It's fine talk about your passion for the employer, but make sure you're talking about your aspirations and commitment to the company, not how much you need a steady paycheck."

Also, keep in mind that even if you aren't saying verbally you're desperate for the job, you may still be conveying it. There are more "subtle points" to an interview, Ankton says, warning that such things as bad posture or a weak handshake can be red flags.

"Your nonverbal cues can say a lot about your personality and interest in the position. Crossing your arms, nodding hurriedly or making tense facial expressions can all send the wrong message," he says.

— By Kathryn Tuggle