As a recruiter, what are the worst interview mistakes for a role in HR you’ve seen candidates make?

The worst interview mistakes I ever met in my practical life are:

Being Negative and telling stories about your personal life's problems.

Negotiating salary expectations in the first meeting.

Being so arrogant.

Trying to impress us with your off-the-wall creativity.

Making your CV three pages long when you have no experience.

Follow the usual pattern and style and tradition, and you do not specify a particular goal to be able to be reached as soon as possible ..

The greatest mistakes that the interviewee candidate could make are:

• to show lack of confidence, assertiveness
• lack of enthousiasm to relate personal life experiences to current employement demands,
• refraining from expressing how their unique creativity could bring a new, enhanced perspective to the organization
• avoid or shy away from setting a concrete basis for salary expectations according to average

Through experience I can select the desired mode with proper planning and not imitate others is familiar with, and goal setting gives the ability to communicate and creativityReceptive greetings and appreciation

I agree with answers given by Maha Abdulhalim, colleen Logan& Nancy Refai, most of their points, I have come crossed during my practical life . 

I fully agree with the answers been added by EXPERTS,,,,,,,,,,,,,,,Thanks.

most of the mistakes are already said by professionals here, but I would just add that i think the biggest mistake people making during interview is that they convincing us in how great and responsible they are, how they reaching targets and tasks, they giving you their reached numbers from previous jobs (which btw i hate when some employers are asking for previous company turnover,this is confidential so we all HR shouldn't forget this) , and everything what i hear is ME, I , ME, I and again ME... they forgetting about team work and showing their team player site... which is REALLY important specially in companies...

1. Candidate answered cell phone and asked the interviewer to leave her own office because it was a "private" conversation.
2. Candidate told the interviewer he wouldn't be able to stay with the job long because he thought he might get an inheritance if his uncle died - and his uncle "wasn't looking too good."
3. Candidate asked the interviewer for a ride home after the interview.
4. Candidate smelled his armpits on the way to the interview room.
5. Candidate said she could not provide a writing sample because all of her writing had been for the CIA and it was "classified."
6. Candidate told the interviewer he was fired for beating up his last boss.
7. When applicant was offered food before the interview he declined, saying that he didn't want to line his stomach with grease before going out drinking.
8. A candidate for an accounting position said she was a "people person," not a "numbers person."
9. Candidate flushed the toilet while talking to the interviewer during a phone interview.
10. Candidate took out a hair brush and brushed her hair mid-interview.

Making your CV three pages long when you have no experience

Being 'low-energy'

Trying to negotiate your salary in the first meeting.

Not knowing anything about the field you’re interviewing for.

First of all candidates did not have adequate knowledge about the company, it's aim & objectives with particular reference to HR policies. Related to this what was their  ignorance about likely task & role in the company with future prospects.

When given situations to be resolved, their reactions were too theoretical. They did not show practicality based on actual conditions prevalent.

When unable to answer a question instead of being honest they would try giving wayward answers.

Sometimes they tended to brag about knowing some senior person in the company.

Overrating their performance in the company they were previously employed in.