All the signals indicate the job is yours: You've endured hours of interviews, and now you're standing in front of the receptionist's desk with a potential colleague, engaging in harmless banter. The topic turns to your current job, and you tell her you can't wait to bail on your psycho manager and out-of-touch CEO.  

You've just shot your chances. Once word gets back to your potential employer about this "harmless" exchange, you're pegged as a malcontent.

"We're all human, and when things start feeling good, we let our guard down," says Dave Sanford, executive vice president of client services at recruitment firm Winter, Wyman & Co. "You can't let your guard down."

Interviews are fraught with opportunities to ruin your chances of landing an offer. Unless you're vigilant, you may sabotage yourself. Check out these tips to stay on your toes.

Don't Get Too Comfortable

Job seekers should not buy into the myth that they should just be themselves during an interview, according to career coach and Monster Interview Expert Marky Stein. "It's a highly ritualized form of interaction," Stein says. "If you think you're not under the most strict scrutiny, you're going to slip up."

Perhaps more than any other mistake, interviewees get too comfortable and lose sight of the fact it is an interview -- a delicate situation requiring a careful dance between the job seeker and interviewer. If you appear too relaxed, you may unintentionally create the impression you don't really care whether you get the job.

Too many people slump back in their chairs, perhaps thinking they look relaxed. "I recommend that people sit right at the edge of their chair," Stein says.

Sanford says job candidates often get too comfortable just at the wrong moment -- when they're getting signals the job is theirs. "What ends up happening is the candidate will start to move from ‘I'm on my best behavior' to thinking ‘the job is mine,' and they stop being deferential," he says. Deference is essential throughout the interview process. Don't act like the interviewer is your best buddy -- he's not.

Follow the First-Date Rule

"I consider an interview like a first date," Stein says. "Interviewees, thinking that they're getting sort of friendly, (sometimes) reveal distasteful things about themselves. Most people on their first date present the best foot forward." That means not telling interviewers about your health problems or financial woes.

Don't Babble or Ramble

When nervous, job seekers often talk too much, sometimes about the wrong things. To avoid rambling, you've got to practice, says Jenna Gausman, a career counselor with Kerwin and Associates. Think about drafting potential interview questions and even conducting a mock interview with a friend or relative.

Show Up Early

Too often, job seekers don't leave themselves enough time to visit the bathroom, check their hair and otherwise feel prepared. Career counselor Judith Gerberg suggests showing up 15 minutes early, giving yourself enough time to visit the washroom. Stretch and yawn, she says, in order to release any tension -- and decrease the likelihood of slip-ups.

Respect Everyone

"These days, people get feedback from whoever you've met," notes Gerberg. "If you're rude to anyone along the line, that will get back to the boss." So be nice to assistants, receptionists and everyone else you encounter along the way.

Don't Drink

Interviews sometimes are conducted over meals or at other social events, which might include alcohol. Never consume alcoholic beverages in interview situations, Stein recommends. You can say something like, "I drink on occasion, but I'll have an iced tea today." Alcohol inevitably makes you let your guard down -- just what you don't want to happen.

Avoid Hot Topics

Religion, politics and other controversial topics should be off limits, says Gausman. Don't think you'll win points by sharing your views on same-sex marriage or stem-cell research.