Job interviews are always stressful. Being hammered with questions about your employment history, the skills that you posses, and how you’d handle hypothetical scenarios is really hard, so you don’t want to mess it up by making an avoidable mistake, like showing up late or failing to bring an extra copy of your resume.

Over the past few years, Robert Half International has surveyed hiring managers and workers, asking them to recount their biggest interview gaffes they’ve either seen or heard. Here are some of the most unforgettable responses–and suggestions on how to avoid falling into the same fate as they did.

Don’t forget your people skills at home:

• ”An individual applied for a customer-service job, and when asked about what he may not like about this job, he replied, ‘Dealing with people.”’
• ”The applicant told me that if she had know it was our company, then she would not have shown up for the interview.”
• ”When asked by the hiring manager why she was leaving her current job, the applicant said, ‘My manager was a jerk. All managers are jerks.”

No matter how well that you have prepared, your nerves may be getting the best of you. Based on the examples above, you definitely wouldn’t be the first person to let nerves control you.

Don’t focus on your needs over the employer’s:

• ”The applicant told me that he was really not interested in the position, but he did like that we were allowed a lot of time off.”
• One individual said that we had nice benefits, which was good because he was going to need to have a lot of leave time next year.”

It’s common knowledge that the interview is a good opportunity to learn more about the position that you are applying for. But make sure to use some common sense when it comes to digging for some more information.

Do not ask for all the nitty-gritty future compensation, benefits and perks until the hiring manager has expressed just how serious he is about offering your the position. Jumping down the gun may make you seem like you don’t care about the job, just the money and the benefits that will come with it.

Do not dress down:

• A person come in to the interview in pajamas with slippers as well.”
• ”The candidate left his dry cleaning tag on his jacket and told everyone that he wanted to show that he was a clean individual.”
• ”An applicant wore the uniform from his former employer.”

No matter how casual a potential employer’s work environment seems, dress to impress everyone. That means that you should wear a suit, or something similar to professional attire.

It’s highly unlikely that a hiring manager is going to knock points off for showing up to the interview over dressed. However, coming in a casual attire may give that impression that you are not very serious about landing the job and the interviewer may not care as much as your answers to his questions.