An interview can seem like a friendly thing -- and it might be -- but it's also an intense test. A company hasn't called you in just to have a nice conversation. It wants to get to know you on a deeper level.

That may take the form of an interrogation, a chat, or some combination of the two. No matter what form the interview takes, you should be prepared to avoid these traps that some companies will set and others will simply watch you fall into. 

People are seen waiting holding papers.

Remember that an interview is a work situation, not a friendly chat. Image source: Getty Images.

1. Don't badmouth your old boss

Even if you worked for an employer that has a reputation for being difficult to work with, try to keep things positive. If the interviewer baits you with a question like "I've heard some terrible stories about..." keep your answer positive. "It was challenging at times, but that taught me things I can bring to my next position, so I'm grateful for the opportunity."

It might be tempting to say something negative, and doing so may get a laugh in the room. But it might also get your potential future employer thinking about whether you might badmouth it sometime down the road.

2. Never be angry

Your old company may have laid you off so the boss could get a fancier car, or maybe you were fired for a reason you believe is ridiculous and unfair. It's OK to be angry in private, but that anger should not be carried over into an interview.

If you get asked about what happened at your previous employer, play it as safe as possible. "Unfortunately, the market took a turn and I was one of the people laid off." Being mad or expressing that you thought things weren't fair simply won't help, and they may cast you in a bad light with the interviewer.

3. Don't be too informal

The interviewer may act like an old friend, and even use very informal language or show up dressed casually. You should always treat an interview like a professional situation. That means dressing appropriately (including a suit for men and the equivalent for women).

Even if the recruiter tells you not to dress that way, don't show up in jeans and a T-shirt. Once you get the job you may be able to dress down and speak informally, but an interview is not the place for that.

4. Don't forget your materials

Even though the interviewer should have printed a copy of your resume, cover letter, and assorted materials, don't assume they did. Have backups of everything you might need, including a list of references. Be prepared for any situation, and assume the person on the other side of the chair hasn't done anything to get ready.

It's game time

You never want to leave an interview feeling like you blew a question because you weren't prepared. Do your homework and go into the interview with some knowledge of the company and insightful questions to ask. You don't have to know everything, but you want to make it clear that you put the work in beforehand.

Show the interviewer that you not only deserve the job, but also that you want it. Be enthusiastic and informed. Make it clear that you would bring positive energy to the company, and that any weaknesses you may have will more than be made up for by effort.